eb1631 Protect Your Groundwater: Survey Your Homestead Environment

EB1631

Protect Your Groundwater: Survey Your Homestead Environment

By Edward B. Adams

This bulletin will help you survey your farmstead for conditions and activities that could damage the groundwater beneath your farm. Because people cannot see what happens below the ground surface, it is easy to be unaware (or forget) how activities affect a homestead's groundwater quality. Although many think that groundwater is pure and unlimited, it is not always pure and the supply certainly has limits.

Familiar causes of groundwater pollution are bacteria and viruses from defective septic systems, livestock wastes, dead animal carcasses, and rodents. Less familiar sources are agricultural chemicals, including pesticides and fertilizers; and petroleum products, such as diesel fuel, gasoline, and motor oil.

Make a Rough Drawing

To start an environmental survey of your homestead, work up a rough drawing of your homestead layout. Include all buildings and animal pens. Locate and mark all areas where chemicals may be stored. Mark the location of your well(s), the septic tank and its drainfield laterals. Also show nearby streams, drainage ditches and ponds. Using arrows, show the general slope of the land and where rainwater flows or pools into standing water.

Inspect the Homestead

Now you are ready to walk through your homestead and buildings. Take your drawing with you. Measure the actual distances as you go. List exactly what is in the garage, the feed room, and the old shed. Keep an open mind. Make a complete inventory of all chemicals stored on your homestead. Include fertilizers, pesticides, paints, solvents, oil, gasoline, household and daily cleaners, etc.

First, Look at Your Well

Wells provide direct access to groundwater for contaminants. Bacteria, rodents, surface runoff, and chemical spills can contaminate wells that are not properly sealed, cased or grouted. Pollutants may then flow from the well directly into groundwater.

Construction. Proper installation protects a well from contamination by surface water. The well casing should have a sanitary seal and be grouted at least 18 feet deep. Or, extend the well casing 5 feet into an impermeable soil layer that caps the aquifer which contains the groundwater.

Abandoned wells. Old well pits, uncapped wells, and abandoned wells–often forgotten–are direct conduits to groundwater. They also pose safety hazards for children. Contact a licensed well driller for information on how to plug an abandoned well. Never use old wells as disposal sites.

Well Head Protection. Even in properly constructed wells, protect the area immediately surrounding the well from contaminants that may flow to, around, or down the outside of the well to groundwater. Site septic drainfields at least 100 feet from your well. Double this distance in sandy soils or near shallow wells. Keep any livestock or poultry confinement areas at least 100 feet from your well to protect groundwater from nitrate and microbes.

Keep fertilizer and pesticide storages at least 100 feet from your well. Do not mix or load these agrichemicals into a sprayer within 100 feet of a well. Never store chemicals in the well house.

Remember that 100 feet is a minimum–greater distances are even better. Moving the well to protect groundwater could be an expensive operation. A better solution may be to move the activity or storage areas farther from the well.

Backsiphoning. Groundwater pumped from the well through pipes to its end use can flow back into the well if power to the pump is lost. This is known as backsiphoning. Install antibacksiphoning (check) valves between the well and water pipes. If water pressure is lost even momentarily these devices prevent siphoning contaminants into the well.

Surface drainage. Direct surface drainage away from the well. Rainwater and snow melt can carry contaminants toward the well from roofs, livestock lots, or chemical handling areas. Other sources of contaminated runoff are malfunctioning septic drainfields, chemically treated fields, and crops. To protect groundwater, drain these areas as far away from the well as practical.

However, do not direct agricultural drainage into dry wells, another conduit to groundwater that should be plugged. Do not divert runoff directly to surface water. A filter strip of grass 50 to 100 feet wide may help filter some contaminants from the runoff and provide a measure of protection for surface water.

Check Your Septic System

Potential Problems. Most rural and many suburban dwellings have a septic tank and drainfield. Older homes may have cesspools. Cesspools are illegal because they discharge raw sewage directly into the ground. Replace cesspools with a septic system.

A septic system settles and treats household wastes such as soapy water from the laundry and the bath, food scraps, and body wastes. The solids settle to the bottom of the tank where bacteria change some organic matter into gases. The clarified liquid flows into the drainfield where it seeps into the soil. Soil microorganisms and filtration by the soil remove most of the impurities in the liquid wastes. A properly designed, operated, and maintained system reduces disease causing organisms to safe levels before the treated wastewater reaches groundwater.

Septic tanks do not remove nitrate or many other chemicals. Nitrate-contaminated groundwater can be a serious health hazard when used for drinking water. Nitrate is a natural byproduct of waste, so proper drainfield siting takes into account the soil profile and a satisfactory depth to the water table. Do not put chemicals that could contaminate groundwater into a septic system.

Maintenance. Once properly constructed, an adequately maintained septic tank system protects groundwater as satisfactorily as a city sewer. However, a system that does not receive the care and attention required may be a menace to groundwater and health.

Have the septic tank pumped regularly. Pump out the tank every 2 to 3 years, or whenever it gets over one quarter full of sludge. The rate of sludge buildup depends on tank size and the volume of solids in the sewage. Septic tank cleaners are not recommended and do not replace pumping.

Tips to reduce septic system problems:

Do not use a garbage disposal (grinder) unless the tank was designed and sized to handle one. The extra solids fill the tank too rapidly. Dispose of this waste in a compost pile with yard waste.
Avoid placing the following materials in the septic tank: paper towels, disposable diapers, rags, sanitary napkins, tampons, cat litter, or other nonsewage materials. These items may plug your plumbing, fill your tank, or even cause the early failure of your drainfield.

Inspect your drainfield for leaks. Indicators of a failed drainfield are wet spots, unpleasant odor, or lush growth of water-loving vegetation. These surface flows are offensive nuisances, and can be a health hazard, particularly to children and pets. They may contain organisms that cause typhoid fever, dysentery, and other diseases. Ponded sewage provides an excellent breeding place for mosquitos and other disease-carrying insects.

These indicators of untreated waste result from system failure. If a septic system is no longer treating wastes as designed, groundwater and drinking water from nearby wells may also be contaminated. Have your city or county health department investigate your septic system to determine corrective measures.

Inspect Your Underground Fuel Storage Tank

Leaking Underground Storage Tanks. Surveys in several states have shown that underground fuel tank leaks and fuel spills contribute significantly to groundwater contamination. Most of these tanks are at service stations, but private tanks on farms can also significantly contaminate groundwater.

An underground storage tank has a maximum life span of 15 to 25 years, and the chance of a tank leaking increases with age. Leaked fuel may seep through the soil to groundwater. Very small amounts of petroleum can contaminate large volumes of groundwater. One part per million of petroleum renders the taste and odor of water unacceptable for drinking.

Petroleum fuels contain toxic compounds, including benzene, toluene, and xylene. Fuels may also contain additives such as ethylene dibromide and organic lead compounds. Lifetime exposures to any of these substances, even in extremely small amounts (parts per billion), may lead to increased cancer rates. These levels are below what smell or taste can detect.

Check your tank for leaks. Consider having your fuel tank tested for tightness yearly. If your fuel tank holds over 1100 gallons you must obtain a permit from the Washington State Department of Ecology (Ecology) and perform leak detection tests as outlined in Chapter 173-360 WAC.

If a leak is detected, immediately empty the tank to stop the flow of fuel into the ground. Repair the empty tank if it is otherwise sound, or replace it. Have the repairs done by qualified service personnel because fumes in a supposedly empty tank can be highly explosive.

Evaluate Your Pesticide Management

Pest Management. One way to reduce pesticide impacts on groundwater is to use all available nonchemical options for pest management. These include pest-resistant crop varieties, biological pest control, and crop rotations. When a pesticide is necessary, select the least environmentally sensitive pesticide that will control the pest. Look for less leachable and less persistent pesticides, if available. Follow all groundwater warnings on the label. Always read and follow all label instructions and precautions. Never apply more pesticide than the rate recommended on the label.

Pesticide storage. Carefully survey your storage areas. Spills are nearly inevitable where containers are handled. Spilling a concentrated formulation is more serious than applying diluted material on a field where the pesticide is designed for use. Build storage areas with concrete floors, and no drain, so spilled concentrates can be cleaned up and disposed of without soil or water contamination.

Pesticide mixing and loading. Pesticides can be spilled on the ground during mixing and loading. Repeated spills increase pesticide concentrations in the soil, which may be unable to absorb or degrade the pesticide. Spills increase the possibility of pesticides leaching down to groundwater. Once contaminated, the groundwater may remain unusable for years. Cleaning a well is prohibitively expensive.

To protect groundwater supplies, load spray equipment and mix pesticides in the field if possible. If you fill sprayer tanks directly from the well, use an anti-backsiphoning valve. If you do not have one of these valves, keep the hose end out of the tank to prevent siphoning the pesticide into the well if the pressure drops. Clean the sprayer (inside and out) while in the field. Spray the rinse water out in the field.

Container Disposal. A pesticide container is never completely empty. The concentrated leftovers are troublesome sources of contamination. Rinse the containers three or more times. Add the rinse water back into the spray tank solution for field spraying. Puncture empty containers to prevent reuse. Dispose of used containers in a sanitary landfill or return recyclable containers to your pesticide dealer.

Check Livestock Waste Handling

Microbial Contamination. Evaluate your homestead sanitation program. A clean homestead protects your groundwater from bacteria and viruses. Cleanliness around grain storage and handling areas and prompt, proper disposal of garbage discourages rodents. If livestock are a part of the operation, practice routine waste disposal. Promptly remove dead animals. Locate confined feeding areas away from wells, streams, and ponds. Do not stockpile manure near any water source.

Nitrate. Animal wastes are a major source of nitrate on many homesteads. Locate livestock and pet pens or corrals away from all wells. A good practice is to use the fertilizer value of animal wastes by spreading them on production fields. If you can not use the manure, perhaps gardeners or other farmers can. Keep stockpiled manure covered to reduce leaching. Divert runoff away from wells.

Put What You Learn into Action

Now that you have completed your survey, think about what you found and take action. List remedial actions or improvements you should take to protect your groundwater and you. Put items that are immediate health concerns first on your list. Some suggested actions follow.

Test Your Well Water

Even if you have no obvious water problems, test household water supplies annually at an approved laboratory. The Washington State Department of Health certifies these laboratories. Have tests run for nitrate, total coliform bacteria, pH, and total dissolved solids. Keep records of your water quality. Watch for changes or deterioration of your groundwater supply. Testing for many other contaminants is possible but expensive and usually not necessary. However, if you have reason to suspect other contaminants, test for them, too.

Properly Dispose Of Hazardous Wastes

Dispose of small, leftover amounts of farm, household, and automotive products to prevent leaks and spills which could damage groundwater. Unused products such as motor oil, transmission fluid, antifreeze, paints, household cleaners and septic tank degreasers are all considered hazardous waste. Give usable products to someone who needs them. Recycle or properly dispose of unusable products. For information on disposal of hazardous wastes, call the Washington State Department of Ecology at 1-800-RECYCLE.

Additional Resources

1. Disposal of Household Hazardous Waste. Washington State University Cooperative Extension. 1989. EB1522.

2. Farm Bureau's Water Quality Self-Help Check-list.

Acknowledgments

Partial funding for publications in this series on Groundwater Protection was obtained through U.S. Environmental Protection Agency nonpoint source pollution grants administered by the Washington State Department of Ecology.

By Edward B. Adams, Ph.D., Washington State University Regional Water Quality Coordinator, WSU Spokane.

The author acknowledges the contributions of Christopher F. Feise. Ph.D., Washington State University Extension Western Washington Water Quality Coordinator and Groundwater Fact Sheet Project Coordinator, WSU-Puyallup Research and Extension Center; John H. Pedersen, Ph.D., P.E., Consulting Technical Editor and retired manager of the Midwest Plan Service, Iowa State University, Ames, IA; and Ronald E. Hermanson, Ph.D., P.E., WSU Extension Agricultural Engineer and Water Quality Project Leader, WSU-Pullman.

Issued by Washington State University Cooperative Extension and the U.S. Department of Agriculture in furtherance of the Acts of May 8 and June 30, 1914. Cooperative Extension programs and policies are consistent with federal and state laws and regulations on nondiscrimination regarding race, color, gender, national origin, religion, age, disability, and sexual orientation. Evidence of noncompliance may be reported through your local Cooperative Extension office. Trade names have been used to simplify information; no endorsement is intended. Reprinted August 1994. Subject code 376. X EB1631

TOP

Protect Your Groundwater: Survey Your Homestead Environment
By Edward B. Adams


This bulletin will help you survey your farmstead for conditions and activities that could damage the groundwater beneath your farm. Because people cannot see what happens below the ground surface, it is easy to be unaware (or forget) how activities affect a homestead's groundwater quality. Although many think that groundwater is pure and unlimited, it is not always pure and the supply certainly has limits. Familiar causes of groundwater pollution are bacteria and viruses from defective septic systems, livestock wastes, dead animal carcasses, and rodents. Less familiar sources are agricultural chemicals, including pesticides and fertilizers; and petroleum products, such as diesel fuel, gasoline, and motor oil.

Make a Rough Drawing
To start an environmental survey of your homestead, work up a rough drawing of your homestead layout. Include all buildings and animal pens. Locate and mark all areas where chemicals may be stored. Mark the location of your well(s), the septic tank and its drainfield laterals. Also show nearby streams, drainage ditches and ponds. Using arrows, show the general slope of the land and where rainwater flows or pools into standing water.

Inspect the Homestead
Now you are ready to walk through your homestead and buildings. Take your drawing with you. Measure the actual distances as you go. List exactly what is in the garage, the feed room, and the old shed. Keep an open mind. Make a complete inventory of all chemicals stored on your homestead. Include fertilizers, pesticides, paints, solvents, oil, gasoline, household and daily cleaners, etc.

First, Look at Your Well
Wells provide direct access to groundwater for contaminants. Bacteria, rodents, surface runoff, and chemical spills can contaminate wells that are not properly sealed, cased or grouted. Pollutants may then flow from the well directly into groundwater. Construction. Proper installation protects a well from contamination by surface water. The well casing should have a sanitary seal and be grouted at least 18 feet deep. Or, extend the well casing 5 feet into an impermeable soil layer that caps the aquifer which contains the groundwater. Abandoned wells. Old well pits, uncapped wells, and abandoned wells–often forgotten–are direct conduits to groundwater. They also pose safety hazards for children. Contact a licensed well driller for information on how to plug an abandoned well. Never use old wells as disposal sites. Well Head Protection. Even in properly constructed wells, protect the area immediately surrounding the well from contaminants that may flow to, around, or down the outside of the well to groundwater. Site septic drainfields at least 100 feet from your well. Double this distance in sandy soils or near shallow wells. Keep any livestock or poultry confinement areas at least 100 feet from your well to protect groundwater from nitrate and microbes. Keep fertilizer and pesticide storages at least 100 feet from your well. Do not mix or load these agrichemicals into a sprayer within 100 feet of a well. Never store chemicals in the well house. Remember that 100 feet is a minimum–greater distances are even better. Moving the well to protect groundwater could be an expensive operation. A better solution may be to move the activity or storage areas farther from the well. Backsiphoning. Groundwater pumped from the well through pipes to its end use can flow back into the well if power to the pump is lost. This is known as backsiphoning. Install antibacksiphoning (check) valves between the well and water pipes. If water pressure is lost even momentarily these devices prevent siphoning contaminants into the well. Surface drainage. Direct surface drainage away from the well. Rainwater and snow melt can carry contaminants toward the well from roofs, livestock lots, or chemical handling areas. Other sources of contaminated runoff are malfunctioning septic drainfields, chemically treated fields, and crops. To protect groundwater, drain these areas as far away from the well as practical. However, do not direct agricultural drainage into dry wells, another conduit to groundwater that should be plugged. Do not divert runoff directly to surface water. A filter strip of grass 50 to 100 feet wide may help filter some contaminants from the runoff and provide a measure of protection for surface water.

Check Your Septic System
Potential Problems. Most rural and many suburban dwellings have a septic tank and drainfield. Older homes may have cesspools. Cesspools are illegal because they discharge raw sewage directly into the ground. Replace cesspools with a septic system. A septic system settles and treats household wastes such as soapy water from the laundry and the bath, food scraps, and body wastes. The solids settle to the bottom of the tank where bacteria change some organic matter into gases. The clarified liquid flows into the drainfield where it seeps into the soil. Soil microorganisms and filtration by the soil remove most of the impurities in the liquid wastes. A properly designed, operated, and maintained system reduces disease causing organisms to safe levels before the treated wastewater reaches groundwater. Septic tanks do not remove nitrate or many other chemicals. Nitrate-contaminated groundwater can be a serious health hazard when used for drinking water. Nitrate is a natural byproduct of waste, so proper drainfield siting takes into account the soil profile and a satisfactory depth to the water table. Do not put chemicals that could contaminate groundwater into a septic system. Maintenance. Once properly constructed, an adequately maintained septic tank system protects groundwater as satisfactorily as a city sewer. However, a system that does not receive the care and attention required may be a menace to groundwater and health. Have the septic tank pumped regularly. Pump out the tank every 2 to 3 years, or whenever it gets over one quarter full of sludge. The rate of sludge buildup depends on tank size and the volume of solids in the sewage. Septic tank cleaners are not recommended and do not replace pumping. Tips to reduce septic system problems: Do not use a garbage disposal (grinder) unless the tank was designed and sized to handle one. The extra solids fill the tank too rapidly. Dispose of this waste in a compost pile with yard waste. Avoid placing the following materials in the septic tank: paper towels, disposable diapers, rags, sanitary napkins, tampons, cat litter, or other nonsewage materials. These items may plug your plumbing, fill your tank, or even cause the early failure of your drainfield. Inspect your drainfield for leaks. Indicators of a failed drainfield are wet spots, unpleasant odor, or lush growth of water-loving vegetation. These surface flows are offensive nuisances, and can be a health hazard, particularly to children and pets. They may contain organisms that cause typhoid fever, dysentery, and other diseases. Ponded sewage provides an excellent breeding place for mosquitos and other disease-carrying insects. These indicators of untreated waste result from system failure. If a septic system is no longer treating wastes as designed, groundwater and drinking water from nearby wells may also be contaminated. Have your city or county health department investigate your septic system to determine corrective measures.

Inspect Your Underground Fuel Storage Tank
Leaking Underground Storage Tanks. Surveys in several states have shown that underground fuel tank leaks and fuel spills contribute significantly to groundwater contamination. Most of these tanks are at service stations, but private tanks on farms can also significantly contaminate groundwater. An underground storage tank has a maximum life span of 15 to 25 years, and the chance of a tank leaking increases with age. Leaked fuel may seep through the soil to groundwater. Very small amounts of petroleum can contaminate large volumes of groundwater. One part per million of petroleum renders the taste and odor of water unacceptable for drinking. Petroleum fuels contain toxic compounds, including benzene, toluene, and xylene. Fuels may also contain additives such as ethylene dibromide and organic lead compounds. Lifetime exposures to any of these substances, even in extremely small amounts (parts per billion), may lead to increased cancer rates. These levels are below what smell or taste can detect. Check your tank for leaks. Consider having your fuel tank tested for tightness yearly. If your fuel tank holds over 1100 gallons you must obtain a permit from the Washington State Department of Ecology (Ecology) and perform leak detection tests as outlined in Chapter 173-360 WAC. If a leak is detected, immediately empty the tank to stop the flow of fuel into the ground. Repair the empty tank if it is otherwise sound, or replace it. Have the repairs done by qualified service personnel because fumes in a supposedly empty tank can be highly explosive.

Evaluate Your Pesticide Management
Pest Management. One way to reduce pesticide impacts on groundwater is to use all available nonchemical options for pest management. These include pest-resistant crop varieties, biological pest control, and crop rotations. When a pesticide is necessary, select the least environmentally sensitive pesticide that will control the pest. Look for less leachable and less persistent pesticides, if available. Follow all groundwater warnings on the label. Always read and follow all label instructions and precautions. Never apply more pesticide than the rate recommended on the label. Pesticide storage. Carefully survey your storage areas. Spills are nearly inevitable where containers are handled. Spilling a concentrated formulation is more serious than applying diluted material on a field where the pesticide is designed for use. Build storage areas with concrete floors, and no drain, so spilled concentrates can be cleaned up and disposed of without soil or water contamination. Pesticide mixing and loading. Pesticides can be spilled on the ground during mixing and loading. Repeated spills increase pesticide concentrations in the soil, which may be unable to absorb or degrade the pesticide. Spills increase the possibility of pesticides leaching down to groundwater. Once contaminated, the groundwater may remain unusable for years. Cleaning a well is prohibitively expensive. To protect groundwater supplies, load spray equipment and mix pesticides in the field if possible. If you fill sprayer tanks directly from the well, use an anti-backsiphoning valve. If you do not have one of these valves, keep the hose end out of the tank to prevent siphoning the pesticide into the well if the pressure drops. Clean the sprayer (inside and out) while in the field. Spray the rinse water out in the field. Container Disposal. A pesticide container is never completely empty. The concentrated leftovers are troublesome sources of contamination. Rinse the containers three or more times. Add the rinse water back into the spray tank solution for field spraying. Puncture empty containers to prevent reuse. Dispose of used containers in a sanitary landfill or return recyclable containers to your pesticide dealer.

Check Livestock Waste Handling
Microbial Contamination. Evaluate your homestead sanitation program. A clean homestead protects your groundwater from bacteria and viruses. Cleanliness around grain storage and handling areas and prompt, proper disposal of garbage discourages rodents. If livestock are a part of the operation, practice routine waste disposal. Promptly remove dead animals. Locate confined feeding areas away from wells, streams, and ponds. Do not stockpile manure near any water source. Nitrate. Animal wastes are a major source of nitrate on many homesteads. Locate livestock and pet pens or corrals away from all wells. A good practice is to use the fertilizer value of animal wastes by spreading them on production fields. If you can not use the manure, perhaps gardeners or other farmers can. Keep stockpiled manure covered to reduce leaching. Divert runoff away from wells.

Put What You Learn into Action
Now that you have completed your survey, think about what you found and take action. List remedial actions or improvements you should take to protect your groundwater and you. Put items that are immediate health concerns first on your list. Some suggested actions follow.

Test Your Well Water
Even if you have no obvious water problems, test household water supplies annually at an approved laboratory. The Washington State Department of Health certifies these laboratories. Have tests run for nitrate, total coliform bacteria, pH, and total dissolved solids. Keep records of your water quality. Watch for changes or deterioration of your groundwater supply. Testing for many other contaminants is possible but expensive and usually not necessary. However, if you have reason to suspect other contaminants, test for them, too.

Properly Dispose Of Hazardous Wastes
Dispose of small, leftover amounts of farm, household, and automotive products to prevent leaks and spills which could damage groundwater. Unused products such as motor oil, transmission fluid, antifreeze, paints, household cleaners and septic tank degreasers are all considered hazardous waste. Give usable products to someone who needs them. Recycle or properly dispose of unusable products. For information on disposal of hazardous wastes, call the Washington State Department of Ecology at 1-800-RECYCLE.

Additional Resources
1. Disposal of Household Hazardous Waste. Washington State University Cooperative Extension. 1989. EB1522. 2. Farm Bureau's Water Quality Self-Help Check-list.

Acknowledgments
Partial funding for publications in this series on Groundwater Protection was obtained through U.S. Environmental Protection Agency nonpoint source pollution grants administered by the Washington State Department of Ecology.


By Edward B. Adams, Ph.D., Washington State University Regional Water Quality Coordinator, WSU Spokane. The author acknowledges the contributions of Christopher F. Feise. Ph.D., Washington State University Extension Western Washington Water Quality Coordinator and Groundwater Fact Sheet Project Coordinator, WSU-Puyallup Research and Extension Center; John H. Pedersen, Ph.D., P.E., Consulting Technical Editor and retired manager of the Midwest Plan Service, Iowa State University, Ames, IA; and Ronald E. Hermanson, Ph.D., P.E., WSU Extension Agricultural Engineer and Water Quality Project Leader, WSU-Pullman. Issued by Washington State University Cooperative Extension and the U.S. Department of Agriculture in furtherance of the Acts of May 8 and June 30, 1914. Cooperative Extension programs and policies are consistent with federal and state laws and regulations on nondiscrimination regarding race, color, gender, national origin, religion, age, disability, and sexual orientation. Evidence of noncompliance may be reported through your local Cooperative Extension office. Trade names have been used to simplify information; no endorsement is intended. Reprinted August 1994. Subject code 376. X EB1631