February 2004 - Amazon S3El Dorado County Environmental Management Department • A Guide for the Private Well Owner • Page 7 pipes connected to the well. If you share a well with

El Dorado County Environmental Management Department • A Guide for the Private Well Owner • Page 2

Table of Contents

Introduction ............................................................ 3

Well Owner Responsibilities ................................. 4

Well Construction and Maintenance .................... 5

Water Quality Protection ....................................... 8

Water Quality Sampling and Treatment ............. 10

Resource Guide.................................................... 15

A Guide for thePrivate Well Owner

February 2004


This brochure is intended to makeprivate well ownership a littleeasier. It is designed to:

• Alert private well owners to thepotential for contamination andthe need for water-qualitytesting;

• Introduce well owners to thebasics of proper wellconstruction, destruction andmaintenance;

• Inform well owners of theirresponsibilities in El DoradoCounty.

The majority of all waterproduced in El Dorado Countywells comes from undergroundfracture zones. The fracture zonesprovide natural storage for thisunderground water source.

In addition to being anextraordinary storage facility, thefracture zones also serve as aninexpensive and efficienttreatment and distributionsystem: as water percolates down,

it is naturally purified and spreadsout for miles to serve a wide area.

The thousands of water supplywells that draw water from thecounty’s groundwater resourceshave traditionally produced veryhigh quality drinking water.

In recent years, however, ourdrinking water fracture zoneshave been threatened by toxicchemicals from industrial spills,leaking underground storagetanks, and agriculturalapplications, as well as biologicalpathogens from sewers, septicsystems and animal facilities.

These contaminants can findtheir way through the naturalprotective layers of clay and siltand into our drinking waterfracture zones.

This problem can be exasperatedby the presence of improperlyconstructed wells, abandonedwells, or wells located too near apotential contaminant source like

a septic system. These wells canact as vertical pathways, allowingchemicals and pathogens on thesurface or in shallow fracturezones, to migrate into our deepdrinking water fracture zones.

To help control and prevent thecontamination of our groundwaterstorage basins and to protectpublic health, we need thecooperation of private well owners.

We have produced this pamphletto help you help us protect ourgroundwater resources and yourhealth.

This pamphlet is meant only asa guide for well owners. We do notclaim that the recommendationsmade in this document will workin every situation. Nor do we claimto have covered every possiblescenario or contaminant. Anyreference to trade names andcompanies does not constitute anendorsement.

AGRICULTURALAPPLICATION

ANIMAL FACILITYSEWERLINE

INDUSTRIAL

SANTA CRUZ MOUNTAINS

CREEK

STORAGETANK

GAS STATION

WATERSUPPLYWELLWATER TABLE

�DIABLO RANGE

DEEP DRINKINGWATER AQUIFER

CLAY & SILTLAYER

SHALLOWAQUIFER

SAND & GRAVELBEDROCK WATER INFRACTURED BEDROCK

GROUNDWATER BASIN

SEPTICSYSTEM

SHALLOWWELL

Introduction

A Typical Water Basin


To protect public health and tomaintain the high quality of waterin our drinking water fracturezones, well owners are required toadhere to various state and locallaws relating to wells. In general,well owners are required to:

•Obtain permits from the ElDorado County EnvironmentalManagement Department (EMD)for any well construction,destruction, or modification.

• Complete any wellconstruction, destruction, ormodification according to EMDand State Well Standards.Wells must be constructed sothat they do not allow poorquality surface water or waterfrom shallow fracture zones tomigrate into drinking waterfracture zones. There arespecific well constructionpractices that must befollowed to ensure that wellsare constructed properly.

Note: all well construction,destruction, or modificationactivities must be completedby a C-57 licensedcontractor.

• Properly maintain the wellso that it remains incompliance with EMD andState Well Standards. Wellsmust be maintained so thatthey do not allow theintroduction of surfacewaters or other materialsinto them throughimproperly sealed wellcasings or gravel fill/sounding tubes. Wells mustbe secured so that childrenor animals cannot enterthem.

• Properly destroy any wellsthat are not being used.

When no longer in use, wellsmust be destroyed so that theycan never act as verticalconduits or endanger publichealth. Generally, wells mustbe completely filled withimpervious sealing materials.

For more information on yourresponsibilities as a well owner, contactthe EMD’s Environmental HealthDivision at 530-621-5300 or in SouthLake Tahoe, 530-573-3450, or visit theEMD’s web site at www.co.el-dorado.ca.us/emd.

Well Owner Responsibilities


Well ConstructionThe typical domestic well in El

Dorado County is constructed bydrilling a hole in the ground tovarious depths, up to 1,000 feet.

As the well driller is drilling thehole, he/she notes the type anddepth of materials that the bitpasses through. This informationis recorded on the Driller Log thatis submitted to the permittingagency and given to thehomeowner.

The well is constructed once thedriller finds a fracture zone thatproduces enough water to meetthe well owner’s needs. Toconstruct the well, the drillerinstalls a length of plastic orsteel pipe called the well casinginto the hole.

The well casing keeps the holefrom collapsing and allowspumping equipment to beinstalled. By regulation, thewell casing must have adiameter at least four-inchessmaller than the diameter ofthe hole.

In cases where the holeintersects water producingfracture zones, the drillerinstalls well casing with thincuts or perforations. Theperforations allow water to passinto the casing but keeps outsand and gravel.

Where the hole intersectslayers of clay or fine silt (layersthat don’t typically producesignificant quantities of water),the driller installs un-perforated pipe called blankcasing.

To protect the water qualityin the deeper, drinking water

zones from poor quality surfacewater and shallow fracture zonewater, the driller also installs aconcrete or cement seal (annularor sanitary seal) between theblank casing and the hole.

In El Dorado County, theminimum annular seal depth is 20feet for domestic wells and 50 feetfor public use water wells.

The annular seal extends to thesurface of the ground where it maybe extended out to create aconcrete pad with the well casing

extending out of the middle of it.These surface features are calledthe wellhead.

At the wellhead, the casingextends at least one foot above theground surface and is securelycapped to prevent anything,including surface water, fromentering the well.

The concrete pad orsurrounding soil is sloped awayfrom the casing to protect the wellfrom damage and from surfacewater contamination.

Well Construction & Maintenance

D E E PA Q U I F E R

C L A Y & S L I T

C L A Y & S I L T

S H A L L O WA Q U I F E R

FilterPack

WellScreen

Wellhead

BlankCasing

Annular orSanitary Seal

S A N D & G R A V E L

WellCasing

Typical Well Construction


Well MaintenanceA poorly maintained well can

lead to a variety of problemsincluding poor water quality andreductions in the amount of wateryour well can produce. Tominimize these potentialproblems, a well maintenanceprogram is an important part of awell owner’s responsibilities.

Inspect Your Wellhead

Get in the habit of doing a visualcheck on your well at least once ayear. More often is better. Seebelow for some of the things tolook for.

Maintain Complete WellRecords

Effective maintenance programsbegin with complete records on theconstruction, testing, andmaintenance of your well. Youshould work with your Water Welland/or Pump Contractor toestablish inspection and routinemaintenance schedules based onthe specific characteristics of yourwell and water supply needs.Complete well records shouldinclude:

• The Driller Log:The document describing theconstruction of the well—howdeep it is, what depth it drawswater from (the perforated

interval), and the soil typesencountered while drilling.This is important informationto help troubleshoot problems,should they arise. The drillingcontractor should provide youwith a copy of the Driller Logfollowing completion of the wellconstruction and testing.

• Pump Test Data:The pump test givesinformation on how muchwater the well can produce.This information is also usefulto assess well performance asthe well ages.

• Distribution Map:Draw a map showing thelocation of all the buried water

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MISSING PLUG

CRACK or GAP

WEEDSor DEBRIS

STANDBYWELL

GROUNDSLOPE

ARTESIANFLOW

3

24

7

REGISTRATION NUMBER

1'

6

Look for openings that insects, rodents, water, or anything else can enter. Cap, seal, or otherwise plug them.

Look for cracks in the concrete pad that would allow water, and any contaminants it may be carrying, to follow the well casing down into your drinkingwater fracture zone. Seal cracks, or re-pour a new concrete pad.

If water is flowing out the top of the well, call a licensed well contractor to stop the flow. In addition to being a waste of water, if water can leak out,contaminants can seep in.

Remove weeds, leaves, and other debris from around your well. These can create great homes for rodents and other pests. Remember, do not useherbicides or any other chemical near the well.

Make sure the ground slopes away from your well and that your well casing extends at least one foot above the ground to ensure that surface waterdoes not collect or flow near the well.

Some counties require a well registration number. El Dorado County DOES NOT.

If you have an inactive well, turn the pump on several times during the year to make sure that everything is functioning properly. Inspect and maintainyour inactive well following the same guidelines as for your active well. If you never plan to use the well again, you are legally required to properlydestroy it. Properly destroying the well will prevent it from being an accidental pathway of contamination into your active well, your neighbor’s well, orthe groundwater.

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pipes connected to the well. Ifyou share a well with adjacentproperties, it is a good idea tohave a map of all the plumbingon your neighbors’ property aswell. This information can beinvaluable as the propertieschange hands and repairs needto be made, or as new wells areadded.

• The Physical Location ofthe Well:Measure the distance to thewell from permanentstructures (e.g. the centerlineof the road or corner of thehouse).

• Maintenance Records:Record whenever you have anymaintenance done, such asreplacing the pump or checkvalves. This is importantinformation to keep track ofhow old the variouscomponents are and whorepaired them last.

• Water Quality Data:Keep all your past waterquality testing information inone place. By comparingresults from one year to thenext you will be better able todetect changes which mayindicate problems.

• Disinfection History:If you disinfect your well, keeptrack of when, why and how itwas done.

Deteriorating WellPerformance

The performance of all wells willdeteriorate over time, but properwell construction and maintenancecan delay this problem.

The typical causes ofperformance deterioration include:mineral encrustation or biofouling(bacteriological encrustation) ofthe well screen, physical pluggingof the well screen, filter pack, andsurrounding soils by fine particles,corrosion of the well casing, andpump problems. Many of theseproblems can be prevented byproper well design andconstruction, proper pump sizing,proper operation andmaintenance, or preventative wellmaintenance. If not allowed toprogress too far, most wellperformance problems can becorrected.

To prevent or correctperformance problems, you shouldwork with your Water Well and/orPump Contractor.

Well Destruction

Any well that is no longer beingused for its intended purpose isrequired by law to be properlydestroyed.

Because unused, abandonedwells can act as pathways thatallow poor quality surface water orshallow groundwater to move intodeeper drinking water zones, it isvery important that they areproperly destroyed. This isespecially true if other watersupply wells are operating in thearea.

When a well is being used in thevicinity of an abandoned well, thepumping activity in the operatingwell can actually pull poor qualitywater down the abandoned well,into the drinking water zones, andthen into the operating well.

To eliminate these verticalpathways for contaminantmigration, abandoned wells mustbe destroyed by filling the entirewell casing with impervioussealing materials.

As with all well construction,modification, or destruction, anywell destruction work must becompleted by a C-57 licensedcontractor and under permit fromthe EMD.


Why Should I Protect TheGroundwater?

For most well owners,groundwater is their only source ofwater and should, therefore, beprotected. Groundwater movesvery slowly, often only a few feetper year, and because it moves soslowly, once it becomes polluted, ittakes years for it to be naturallyflushed clean. Removingpollutants from groundwater canbe extremely costly and difficult.Often, the only solution is to find anew source of water.

What Can I Do To Protect TheQuality Of My Water?Always keep in mind that you liveon top of your drinking water. Thelayer of earth between you and thewater provides some protection

from contamination, but it is notperfect. The safest way to protectyour water supply is to teach yourfamily, friends and neighbors: IfYou Don’t Want To Drink It, Don’tPut It On or In The Ground!

Create A Zone Of ProtectionAround Your Well

Your well is a direct connectionbetween you and your watersupply. Contaminants can flowdown your well as easily as waterflows up it. The farther away fromyour well you are, the more sand,gravel and clay there is to filterout contaminants before theyreach your water supply. So createa circle at least 50 feet in diameteraround your well where you don’tstore, mix, spray, spill, bury ordump anything that you don’t

want to drink. Don’t forget to lookout for your neighbor’s well if it isnear your property line. Anycontamination in your neighbor’swell can travel into your well.

Some activities legally requiremore than a 50-foot zone ofprotection. For example, septictanks, leach fields, and animalenclosures need to be at least 100feet away from any well to ensurethat no waste products reach yourdrinking water. There are manyactivities that do not have formal,legal setback requirements. Useyour common sense. For example,don’t tie your dog or goat to thewell structure—not only do yourisk breaking the casing, piping orelectrical connections, you riskcontamination from urine andfeces.

Water Quality Protection

WELL

0-50'

50'-100'

100'+

Well Setback Distances


Septic System Diagram

LIQUID LAYER

FLOATING SCUM

DO NOT DUMPHAZARDOUSCHEMICALS

PARKING HEAVYVEHICLES CAUSESCOMPACTION

TREES WITHPENETRATINGROOTSROTATE DIVERSION

VALVE ANNUALLY

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GREEN SOGGY AREA(Call Inspector ASAP)

SEPTIC Service

POISON

S E P T I C T A N K

SOLIDS LAYER

INSPECT & PUMP SEPTICTANK EVERY 3-5 YEARS

KEEP SOLIDS TO A MINIMUM(Do not use toilet as a garbage can)3

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L E A C H F I E L D

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Maintain Your Septic System

A septic system consists of a tankand a leach or drain field. All thesolid/liquid waste from inside thehome flows into the septic tank. Theseptic tank is composed of twocompartments. The waste isdeposited in the first compartmentwhere the solids settle to the bottomand the liquid and scum float aboveit. Bacteria and othermicroorganisms break down thesolid material. As theliquid separates from

the solids, it overflows into thesecond compartment where moreseparation and decomposition occurbefore it flows into the leach/drainfield. The leach/drain field is anetwork of perforated pipes within atrench of washed drain rock buriedabout two to three feet deep. Theliquid waste flows out of theperforated pipe and into the soilwhere more pollutants are removed.By the time the wastewater reachesthe groundwater, few impurities

should remain.

If you have a septic

system, keep in mind that whatevergoes down the drain may find itsway into your drinking water. Therequired 100-foot setback betweenyour well and your septic systemprovides relatively good protectionagainst bacteria and viruses when itis working properly.

However, this setback was notdesigned to protect against thingslike photographic processingchemicals, hazardous art supplies,hazardous household cleaners, paintand paint cleaners, automotivewastes, pesticides, and otherhazardous chemicals that may notbreak down and filter out as easily.

Inspect Your Wellhead On ARegular BasisIt is very important to keep anyforeign materials – including surfacewater – out of your well. It should befree from openings and your concretewell pad should be structurally sound.Annual inspections help assure thereare no openings in the wellhead orcracks in the well pad. Any openingsor cracks should be secured or sealed.

Protect The Well StructureMany well repairs can be very costly,so it pays to protect your well fromany physical damage.The safest wayto protect your well from beingdamaged is to build a smallstructure or fence around it. If you

don’t have a structure around yourwell, then clearly mark it so whenthe weeds grow up in the spring, itdoesn’t become buried and lost. Also,lock the well enclosure to minimizethe chance of vandalism.

Do not dump hazardous chemicals down thedrain. If your drain is plugged try using boilingwater or a drain snake instead of chemical draincleaners. Use less toxic cleaning supplieswhenever possible. Take all hazardous chemicalsto a hazardous waste drop-off for disposal.

If you notice a sewage smell, a continuously wetarea in your yard, lush vegetation around theseptic tank or leach field, or liquid waste backingup through your drains, then something is notworking properly. Call a licensed septic tankinspector immediately.

Have your septic tank inspected and pumpedevery three to five years (more often if you havea garbage disposal). If the solid waste in the tankbuilds up too high, it can flow into the leach lines,plug them and cause your system to fail.

Keep the solids in your system to a minimum.Do not use your toilet as a garbage can. Foodwastes, feminine hygiene products and otherhousehold solids are better placed in the garbage.

Do not park or drive heavy equipment over yourleach lines. This may compact the soil aroundthe lines and prevent adequate percolation of the

liquid waste, causing your system to fail.

Do not plant trees near your leach line. Tree rootsoften seek the moist environment inside your leachlines and plug them, causing your system to fail.

If you have a dual leach field system, change thediversion valve setting once a year.

Do not use septic tank additives, yeast, bacteria,enzymes, or other products to enhance thesystem. None of these products have beenproven to be beneficial and some can causepermanent damage.

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As water travels over the surfaceof the land or through the ground,it dissolves naturally occurringminerals and can pick upsubstances resulting from thepresence of animals and humanactivity. Contaminants that maybe present include:

• Microbial contaminants, suchas viruses and bacteria, thatmay come from sewagetreatment plants, septicsystems, agricultural livestockoperations, and wildlife.

• Inorganic contaminants,such as salts and metals,that can be naturally-occurring or result fromurban stormwater runoff,industrial or domesticwastewater discharges,animal facility wastegeneration, mining, orfarming.

• Pesticides and herbicides,that may come from avariety of sources such asagriculture, urbanstormwater runoff, andresidential uses.

• Organic chemicalcontaminants, includingsynthetic and volatileorganic chemicals, thatare by-products ofindustrial processes andpetroleum production, andcan also come from gasstations, urban stormwaterrunoff, agricultural application,and septic systems.

• Radioactive contaminants thatin our area are typicallynaturally occurring.

Drinking water, includingbottled water, may reasonably beexpected to contain small amounts

of some contaminants. Thepresence of contaminants does notnecessarily indicate that the waterposes a health risk. Moreinformation about contaminantsand potential health effects can beobtained by calling the USEPA’sSafe Drinking Water Hotline (1-800-426-4791).

Some people may be morevulnerable to contaminants indrinking water than the generalpopulation. Immuno-compromisedpersons such as persons with

cancer undergoing chemotherapy,persons who have undergoneorgan transplants, people withHIV/AIDS or other immunesystem disorders, some elderly,and infants, can be particularly atrisk from infections. These peopleshould seek advice from theirhealth care providers about theirdrinking water supply.

The most common groundwatercontaminants of concern arebacteria and nitrate.Bacteriological quality of drinkingwater is determined by analyzingfor coliform bacteria. Thesebacteria occur naturally in theintestinal tracts of humans andanimals and in soil. Althoughcoliform bacteria normally do notcause illness, they should not bepresent in drinking water. Thepresence of these bacteria in thedrinking water indicates that the

water may be contaminatedwith other organisms that cancause disease. Diseasesymptoms may typicallyinclude diarrhea, cramps,nausea, and any associatedheadaches and fatigue.Bacteria levels can fluctuateseasonally with wet and dryperiods.

Nitrate is a naturallyoccurring compound, but highamounts of nitrate ingroundwater are typically dueto human activity such asfertilizer applications, septicsystems, and animalenclosures. Nitrate indrinking water at levels above45 milligrams per liter (mg/L)N03 or 10 mg/L NO3-N is ahealth risk for infants of lessthan six months of age,pregnant women and people

with certain specific enzymedeficiencies. Nitrateconcentrations in groundwatermay rise quickly for short periodsof time because of rainfall oragricultural activity. If you arecaring for an infant or arepregnant, you should seek adviceabout your drinking water fromyour health care provider.

Water Quality Sampling & Treatment


Water QualitySamplingWhat Should I Test My WaterFor?

There are dozens of tests thatcan be performed on drinkingwater and no one analysis canassure that your water is “safe todrink.” We have tried to compilethe most commonly performedtests and their recommended

testing frequencies BELOW. Thistable should be used for generalguidance only. Since coliformbacteria and nitrate are the mostcommonly found contaminants ofconcern, we recommend testing forthem most frequently.

Electrical conductivity (EC) is ameasure of all the dissolved ionsin your water. By itself, EC doesnot tell you if your water is safe todrink. However, since the

electrical conductivity test is thecheapest and easiest, it can beused as an indicator of changingconditions that may requirefurther testing.

The minerals tests arerecommended in order to establisha baseline understanding of thewater quality in your well and as amechanism to indicate waterquality changes.

Interpreting Your Results

Then you may want to consider one or more of the following options:

Eliminate cause, disinfect and retest (see page 13).

Increase testing frequency

Install a treatment system such as distillation, chlorination, ozonation, or ultraviolet radiation. Consult a water treatment professional for more advice.

Install a treatment system or find an alternate water supply. Reverse osmosis, distillation, or anion exchange, will remove some of the nitrate. Consult a water treatment professional for more advice.

Increase testing frequency

Conduct further testing, such as nitrate and/or minerals to determine the cause of the high EC, or the change in EC.

Compare to previous results

Install a treatment system or find an alternate water supply. The appropriate treatment system is dependent on your overall water chemistry and what constituents you would like to remove. Consult a water treatment professional for more advice.

Test

Total ColiformBacteria

Nitrate

Electrical Conductance (EC)

MINERALS

Aluminum (Al) Arsenic (As) Barium (Ba) Cadmium (Cd) Chromium (Cr) Fluoride (F) Iron (Fe) Lead (Pb) Manganese (Mn) Mercury (Hg) Selenium (Se) Silver (Ag)

RecommendedFrequency

Twice per year:Wet seasonDry season

Annually

Annually

Every 5-10 years, orIf EC changes significantly, orIf taste, color, odor or surrounding land use change

Cost

$20 – 50

$25 – 45

$12 – 20

Package$250 – 300

Individual $20 – 30

Mercury $30 – 40

If the lab report shows:

Present

≥ 45 mg/l NO3or≥ 10 mg/l NO3-N

≥ 1600 µmhos/cm or significantly different from previous year result

Al ≥ 0.2 mg/l As ≥ 0.05 mg/l Ba ≥ 1.0 mg/l Cd ≥ 0.005 mg/l Cr ≥ 0.05 mg/l F ≥ 2.0 mg/l Fe ≥ 0.3 mg/l Pb ≥ 0.015 mg/l Mn ≥ 0.05 mg/l Hg ≥ 0.002 mg/l Se ≥ 0.05 mg/l Ag ≥ 0.1 mg/l

≥ is greater than or equal tomg/l is milligrams per liter. 1 mg/l = 1 part per million (ppm). 1 mg/l = 1000 microgram per liter (µg/l). 1µg/l = 1 part per billion (ppb)

Recommended Test


What Do I Test For When My Water Has Specific Taste, Odor, Or Appearance Problems?Below is a guide for some potential problems in drinking water and substances you can test for (in bold). Not allof the problems and possible causes pose a health risk to the consumer.

Water is orange or reddish brown

Porcelain fixtures or laundry are stained brown or black

White spots on the dishes or white encrustation around fixtures

Water is blue

Water smells like rotten eggs

Water heater is corroding

Water appears cloudy, frothy or colored

Home’s plumbing system has lead pipes, fittings, or solder joints

Water has a turpentine odor

Water has a chemical smell or taste

Possible CauseProblem Health Risk Category*

This may be due to high levels of iron (Fe).

This is commonly a result of high manganese (Mn) and/or iron (Fe) levels. As little as 50 parts per billion (ppb) manganese and 300 ppb iron can cause staining.

High levels of calcium (Ca) and manganese (Mn) can cause hard water, which leaves spots. Hardness can also be measured directly.

Blue water or blue deposits may be due to high levels of copper (Cu), especially if coupled with corrosive water.

This is most likely caused by hydrogen sulfide (H2S).

Water can be corrosive, neutral, or noncorrosive. Water that is very corrosive can damage metal pipes and water heaters. The lab can calculate the corrosivity of your water by measuring calcium, pH, total dissolved solids (TDS), and alkalinity.

Suspended particulates, measured directly or as turbidity, can cause the water to appear cloudy, frothy or colored. Detergents and/or sewage waste may also be the culprit.

Corrosive water can cause lead (ppb), copper (Cu), cadmium (Cd), and/or zinc (Zn) to be leached from lead pipes, fittings, and solder joints.

This may be due to methyl tertiary butyl ether (MTBE)

This may be due to volatile or semivolatile organic compounds (VOCs) or pesticides.

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Landfill, industry, or dry cleaning operation

Agricultural crop production

Livestock enclosure, manure, or compost storage area

Gas station or automobile repair shop

Consider testing for volatile organic compounds (VOCs), pH, total dissolved solids (TDS), chloride (Cl), sulfate (SO4), and metals.

Consider testing for pesticides commonly used near the well (consult the farmer or Department of Agriculture for a list), nitrate (NO3), pH, and total dissolved solids (TDS).

Consider testing for bacteria, nitrate (NO3), and total dissolved solids (TDS).

Consider testing for total petroleum hydrocarbons (TPHg), total oil and grease (TOG), benzene, toluene, ethylbenzene, xylenes (BTEX), MTBE, ethylene dibromide (EDB).

1* No known health risk at commonly found concentrations

Some of the possible causes can have a detrimental effect on health even if present in low concentrations2

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Health Risk Category*Possible ContaminantsLand Use

Are You Concerned That A Nearby Activity May Be Contaminating Your Well?Below are some land uses and possible contaminants you may want to test for.


Water Quality TreatmentWhat If My Total Coliform Test Results Are Positive?

Step 1. First, try to determine where the contamination came from. The table below lists some possibleproblems and some recommended corrective actions. Some problems you may be able to fixyourself; others – marked by an asterisk (*) – legally require the assistance of a C-57 licensedwell contractor.

For a list of C-57 licensed professionals, visit the EMD website, www.co.el-dorado.ca.us/emd.

The well is newly constructed, or maintenance or repair was recently done.

The pump was primed with impure water.

There is standing water around the well or water draining toward the well.

The concrete well pad is cracked or separated from the well casing.

The well is not completely sealed against surface water, insects, or other foreign matter.

The storage tank is dirty or unprotected.

There are cross-connections in the plumbing system.

There is not adequate back-flow protection.

There are dead-end or unused water lines connected to your plumbing system.

The well casing is corroded.

There is sediment at the bottom of the well.

The well casing is perforated too high or the sanitary seal is not adequate.

Go to step two below.

Re-grade around the well so the ground slopes away from your well.

Re-pour pad or fix and seal all cracks and gaps.

Replace any missing plugs, cap any open pipes, and seal any openings, gaps or cracks.

*Contact a licensed well contractor to replace or install a new wellhead gasket.

Contact a water system contractor to clean and seal.

Make sure that your plumbing is not connected to another source of water that may be contaminated (e.g. a defunct community water system).

Install a back-flow prevention device on every outdoor faucet (available at most hardware and plumbing supply stores).

*Contact a licensed well contractor to ensure that there is proper back-flow protection within the well. Flush lines regularly or

Remove any unused lines or sections of the water system.

*Contact a licensed well contractor to assess and repair.

*Contact a licensed well contractor to drill a new well and to properly destroy the old well.

Recommended Corrective ActionProblem

Step 2. Once you have located and eliminated the source of the bacteria, disinfect the system. Forinstructions on how to properly disinfect your well and distribution system, visit the El DoradoCounty Environmental Management Department web site at www.co.el-dorado.ca.us/emd or,call 530-621-5300 or in South Lake Tahoe, call 530-573-3450, or call a licensed water systemcontractor.

Step 3. IMPORTANT: before drinking the water, test a new sample for total coliform bacteria. If theresults are still positive, start at Step 1 again.


What Can I Do About Other Problems With My Drinking Water?

Most groundwater does not require any treatment. If you have had your water tested and found a problemthat you want to treat, there are many different types of treatment available. Not all water treatment systemswork for every contaminant or forevery water type.

Once installed, most systemsrequire routine maintenance tocontinue performing properly.Improperly maintained systemscan cause more damage thanhaving no system at all.

You need to know what you wantto remove and if you will be able toperform the routine maintenancebefore you invest any money in asystem. See the guide on the rightfor the options available for yourparticular problem(s).

Some options remove a greaterpercent of the concentration thanother options listed for the samesubstance.

We highly recommend that youtalk with the manufacturer or awater treatment professional to geta guarantee that the system youare considering will work in yoursituation. Some water may need tobe softened or pre-filtered or thepH may need to be adjusted priorto treatment.

Contaminant Ultra

viol

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Ozo

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Reve

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Osm

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Mec

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iltra

tion

Oxi

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Chlo

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Dist

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ion

Ani

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Catio

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chan

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Sof

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Act

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arbo

n Fi

lters

7

Act

ivat

ed A

lum

ina

Filte

rs

Air

Strip

ping

X X

X X XX

X XX

X X X X X XX

XXX

XX

XX

X

X

X

X XX X X X

X6

X5

X2 X1

X1

X1

X1

X4

X X

XX

X

XXXXXX

XX

XXX

X

X3X

X

XXX

X X XX

X XXXX

XXX

Arsenic

Asbestos

Atrazine

Benzene

Chlorine

Coliform bacteria

Color

Flouride

Hardness

Hydrogen sulfide

Inorganics, minerals (some)

Iron/manganese — dissolved

Iron/manganese — insoluble

Lead

Mercury

Nitrate

Odor and taste

Pesticides (some)

Radium

Radon gas

Salt

Sand, silt, clay (turbidity)

Volatile organic chemicals (some)

1 When followed by mechanical filtration or an activated carbon filter2 When present in low concentrations3 Only for volatile organic chemicals with high boiling points4 Other water quality problems may interfere with treatment5 With zeolite softening6 Often requires pretreatment system7 There are several different types of activated carbon filters (e.g. granular, block, powder, etc), not all types work on all

substances listed.

Table adapted from the Water Quality Association and from 1996. Rick Weinzierl, et.al (1996). “57 Ways to Protect Your Home Environment (and Yourself),” University of Illinois at Urbana-Champaign, North Central Regional Extension, Publication 583.

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February 2004 - Amazon S3El Dorado County Environmental Management Department • A Guide for the Private Well Owner • Page 7 pipes connected to the well. If you share a well with

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