Local officials often become involved in providing water for the community. Every homeowner wants a water supply that is safe to drink and pleasant to use. A public water system must make several provisions to ensure that a water supply remains safe. Regular water testing is one important tool that a water system uses to protect its customers.
If water testing reveals a water quality problem, four options can be used to solve a problem: 1) better protect the water supply, 2) locate and eliminate sources of contamination, 3) develop a new water supply, or 4) treat the water. Each option should be considered to determine which is the most effective and affordable.
Protecting a water supply through wellhead or watershed protection may be effective at reducing or eliminating problems with bacteria and other disease-causing organisms, nitrates, or synthetic organic chemicals. Water supply protection is most effective before contamination occurs. Protecting a water supply is an ongoing responsibility and must be considered routinely.
A properly protected well has a number of important features, as shown in Figure 1. The well casing must extend above the ground surface and flood levels. The top of the casing should be covered with a sanitary well seal. Surface water must never be allowed to flow down into a well. The ground around the well should slope away to divert all rain and runoff water. Well grouting is critical for keeping water from the ground surface from entering a well. At the time of construction, a driller should fill the space between the bore hole and the casing with bentonite grout or neat cement. Soil or rock cuttings, often used to fill the space between the bore hole and the casing, are not suitable because they do not restrict the flow of water.
Figure 1. Features of a properly protected well.
Wellhead protection extends beyond the well itself. A number of land use activities may cause water supply contamination. Figure 2 illustrates minimum isolation distances between a water supply well and potential sources of contamination.
Wellhead protection is an important community planning process. The Ohio Environmental Protection Agency (EPA) Division of Drinking and Ground Waters provides technical guidance to communities developing a wellhead protection plan. A series of fact sheets on wellhead protection and a video are available from Ohio EPA through one of their five district offices.
Protecting a pond or reservoir from contamination is more difficult than protecting a well. Good land use stewardship is critical. Steps must be taken to limit erosion into streams that lead to ponds and reservoirs. Chemicals and fertilizer application must be managed to match the needs of the crop. Maintaining vegetated buffer areas around the water supply and all of the streams that flow into it will help filter contaminants from runoff water. A detailed discussion of land use practices to prevent contamination of Ohio's ground and surface waters is included in Bulletin 818, Best Management Practices, available from an Ohio county Extension office.
Finding the source of contamination is another approach to solving a water quality problem. While often difficult to locate or correct, some contamination problems can be corrected by eliminating the source. Lead contamination of water from corrosion of metal plumbing and solder is one water quality problem that can be eliminated by replacing pipes, fittings, and fixtures that contain lead. Contamination from leaking fuel tanks, salt storage, or a failing sewage system may also be reduced or eliminated by locating and removing the source of contamination.
Figure 2. Minimum sanitary isolation distances between a well and possible sources of contamination. The minimum isolation distance increases with increasing water usage. Wellhead protection areas would extend even farther. For example, a 50-foot isolation distance is necessary for a water supply using up to 2,500 gallons per day (gpd). However, 300 feet is required for a water supply using up to and more than 50,000 gallons per day.
If a water supply is extensively contaminated by nitrate, salt, fuel, pesticides, or other organic chemicals, abandoning the supply and developing a new one may be the only practical option. Drilling a new well, developing a surface water supply, or purchasing water from an existing water system are all options. Careful evaluation by geologists, engineers, and other professionals is usually necessary to insure that a new supply will be protected.
Because the average person drinks less than 1/2 gallon of the more than 50 gallons of water each person uses in a day, it may be possible to supply a different drinking water source while the community is considering its options. Water that is undesirable for drinking may be acceptable for washing clothes, bathing, and flushing toilets. Bottled water may be a feasible option for supplying a separate drinking water source for a short period.
Water treatment to remove contaminants is a well-recognized approach to solving a water quality problem. Water treatment is most often used to disinfect water supplies to eliminate a bacteria problem and to correct nuisances, such as water that is hard or contains iron and/or hydrogen sulfide.
All water treatment equipment requires maintenance to ensure proper operation. Unfortunately, no single water treatment system can correct all water quality problems. Each treatment approach has its advantages and limitations. The objective is to select a treatment system that provides the advantages you want with limitations you can live with.
A safe and reliable water supply is a fundamental aspect of the quality of people's lives. No quick fixes are available to correct a water quality problem, though many are sold. Proper operation and routine water testing is critical in managing any water supply. Many water quality problems can be avoided through a wellhead or watershed protection program. If problems are discovered, consider all four options to find the most appropriate solution for your community.
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Keith L. Smith, Associate Vice President for Ag. Adm. and Director, OSU Extension.
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