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Keuka Lake Association


Most Americans take water for granted. They have clean, safe water supplied by a municipal water facility where the quality is regulated by state and federal authorities. The forty million Americans who draw water from a spring, lake, well, or cistern have a responsibility to monitor, maintain, and treat the water they drink. This chapter will explain how people with private water systems should operate, test and treat their water to ensure a safe, potable source of drinking water. 

Water is known as a symbol of purity and is essential for life. It can also be the carrier of disease if not properly protected and treated. The great plagues that decimated world populations in the Middle Ages were caused by contaminated drinking water. Waterborne diseases such as cholera, dysentery and hepatitis A are still common in undeveloped countries and occasional outbreaks in our country still take place. Recently, a large outbreak of cryptosporidium (a waterborne parasite) in Milwaukee infected more than 400,000 people and led to over 100 deaths from contamination of the city's public water supply by cattle in feedlots. This catastrophic event drew national attention to the treatment of public water and a heightened awareness to the susceptibility of our water supplies to contamination. 

Public water systems are state and federally regulated and use extensive disinfection technology and personnel to monitor to ensure a potable water supply. Homeowners with personal water supply systems make the critical decisions about treatment and maintenance on their own. Many of the residences around Keuka Lake report that they do not treat their water, " Haven't in the past - don't need to now!" They assume that Keuka Lake is pure and uncontaminated. The reality is that a waterline in Keuka or any of the other Finger Lakes is subject to drawing water which at times may be unsafe to drink. 

We don't know the true extent of waterborne disease from private water supplies because most cases of individuals getting sick from their water go unreported. People often attribute their illnesses to other causes, such as the flu or food poisoning, not realizing their water supply has been contaminated. To protect the public, the New York State Department of Health (NYSDOH) has created health laws (State Sanitary Code Subpart 5-1) regulating the treatment of water for public water systems. These laws regulate municipal water systems, businesses, and any system that services at least 5 homes or 25 individuals. Many of the camps, trailer parks, and small clusters of homes in the Keuka Lake area using a single water source are subject to regulation. Under these laws the minimum treatment for ground water is chlorination or other disinfection methods described by the NYSDOH. Surface water systems come under the Surface Water Treatment Rule which requires slow sand filtration and disinfection of the water before distribution to the users. 

Municipal Water Treatment

About 9,600 people in four communities depend on municipal water drawn from Keuka Lake. Currently the Villages of Hammondsport and Penn Yan chlorinate and fluoridate their lake water. The Village of Dresden gets its water from Penn Yan and Keuka Park chlorinates for Keuka College and the surrounding community. 

In 1997 the Village of Penn Yan will complete construction of a brand new water treatment plant built to comply with the Surface Water Treatment Rule (SWTR). The plant is being built to treat a maximum of 1.77 million gallons of water per day, and was designed to be able to expand to 3 million gallons per day to meet future water needs. So far the Villages of Penn Yan and Dresden, Keuka Park, and part of the Town of Milo are going to be supplied by the plant. There are several other municipalities considering linking up to the waterline in the future. Hammondsport's system already meets the SWTR laws. 

Private Water Sources

Homeowners who do not have a municipal water supply available are responsible for properly testing, treating, and maintaining their water. This requires an understanding of the potential sources of contamination and knowing how they cause problems for water supplies. 

Groundwater is the source for wells, spring boxes, and surface waters, such as streams and lakes, and are subject to contamination from many sources. Leaky underground storage tanks, failed septic systems, manure spread on frozen soil, too much fertilizer on a lawn, fuel spills, etc... are all sources of pollution that can seep through the soil and bedrock to groundwater or flow overland into streams and lakes. For these reasons shallow wells, particularly old wells with unsealed linings of rock or stone, and surface water supplies are the most susceptible to contamination, but even deeper wells are at risk. 

For those who draw water from Keuka Lake, zebra mussels are another problem to contend with. The mussels prefer to settle on hard surfaces with flowing, which makes a water intake pipes an ideal habitat. Eventually, pipes may be clogged, and the water entering the home contaminated as mussels die. When designing a new water system or upgrading a current system, zebra mussel infestation control is just as important as actual water treatment. There is more on controlling zebra mussels in your water system in Chapter 10: Zebra Mussel Control. 

Testing Your Water

Private water supplies should be tested on a regular basis. The frequency of testing depends on well location, construction, and on previous test results. Testing every two to three years may be sufficient for wells that have no history of contamination, are isolated from pollution sources, and have at least 50 ft of watertight casing. Shallow wells, wells that have been previously contaminated, and wells without a watertight casing (such as dug wells or lake water) should be tested at least once per year, preferably in the spring. Lake water tests should be interpreted with caution because there can be small plumes of contaminated water moving about the lake. The water quality may be perfect the majority of the time but can change very quickly as a plume move into the area of the intake. Because of this uncertainty in the water quality, testing the lake for potability is not necessary. The following section describes the process of selecting what types of tests to have done and how to go about testing your water. 

Testing water for every contaminant is possible but very expensive and usually not necessary. It is more important to test on a regular basis for a few indicators of contamination and to maintain a record of water quality. This helps to identify changes in the supply, contamination of the water source or deterioration of the water system. Good records of water quality are also important should you need to prove that your water has been contaminated by some outside activity such as mining or waste disposal. Standard laboratory procedures identify the amounts of specific bacteria, chemical compounds and other components that affect water quality. Most important are routine annual water tests even if no obvious water problems exist. It is recommended that household water be tested for: total coliform bacteria, nitrate, pH, and total dissolved solids. 

Potential for Contamination

Many situations may lead homeowners to suspect that their water supplies are contaminated. Routine water tests, as described previously, are especially important if the supplies are threatened by nearby activities. Both past and current land use practices are important considerations when deciding which tests to perform. They provide a clue as to the most likely pollutant to test for. One way to obtain information on previous land use is from the local planning or zoning board. The effects of previous land uses can give long-lasting impacts on the quality of underlying water. Some contaminants will adhere to certain soil types and be released slowly into percolating water. Table 8-2 list activities that may affect water supplies and offers guidance on which laboratory tests to request if a problem is suspected. 

Land use practices within the area contributing to the water supply should be investigated. For groundwater supplies, the direction of groundwater flow and the aquifer properties have an impact on the area contributing to the well or spring. The soils in the area, the depth to groundwater, and the underlying geology affect the connection between the land surface and the water supply. 

Individual sewage treatment systems that are properly designed and maintained will not contaminate drinking water supplies. Systems that are too closely spaced, poorly maintained, located in poor soils, or located in areas with shallow depths to groundwater pose the greatest danger to drinking water supplies. 

Fuel storage tanks are a potential source of groundwater contamination. They occur in virtually every community, on many farms, and in other areas. Underground storage tanks are particularly dangerous, because their leaks may not be noticed until it is too late. 

Groundwater that has been contaminated by hydrocarbons has a characteristic oily odor. Since hydrocarbons are lighter than water, they tend to drift along the top of the aquifer's saturated zone in the direction of groundwater movement. A hydrocarbon scan can verify the existence of hydrocarbons in groundwater. If a leak is discovered, it does not necessarily mean that local groundwater is contaminated. Unsaturated soil between the tank and the water table may absorb the initial discharge of fuel. 

Proactive maintenance is called for on underground storage tanks. Tank owners are encouraged to have their tanks tested to determine if they are leaking. Old, unused tanks should be dug up and removed. New tanks should be installed above ground where they can be monitored. 


Bacteriological - The presence of coliform bacteria, which are not harmful themselves, is a good indicator of the presence of other, pathogenic (disease causing) bacteria. The inexpensive and simple test for coliform bacteria determines if a water supply is potable or bacteriologically safe to drink. This test identifies drinking water that has been contaminated by human wastes, animal wastes, soil, or plant materials. A positive test result indicates the presence of coliform bacteria and requires further tests are to determine their source. The coliform bacteria test is easily performed by laboratory professionals and can be run routinely at a low cost. 

It is strongly recommended to run a bacteriological test when:

  • there is any noticeable change in color, odor, or taste of the water;
  • high water or flooding covers the top of the well;
  • family members or house guests have recurrent incidents of gastrointestinal illness;
  • the water is going to be used by an expecting mother;
  • there has been any maintenance on the water supply system;
  • a well is newly constructed or repaired;
  • a neighbor's well is found to be unsafe; or
  • you are about to start using a well that has not been in use for a long time.

Nitrate - Nitrates are tasteless and odorless and may be a problem for at risk individuals. A water test is the only way to determine if nitrate is in the water supply. Testing for nitrate should be done if any of the following are in the area of the water supply: livestock facilities, fertilizer storage or handling sites, septic systems, or other nitrogen sources. Spreading manure or municipal sludge on land and over-application of fertilizer to agricultural crops also may lead to nitrate contamination. 

Babies are most sensitive to excessive nitrates in drinking water. If a newborn is expected in a household and there is a potential for nitrate contamination, testing for nitrate is recommended in the early months of pregnancy. Testing should also be done before bringing an infant home, and again during the first six months of the baby's life. The possible consumption of water with a concentration of nitrate greater than the 10 ppm (the maximum contaminant level) puts the baby at risk of developing methemoglobinemia, also called blue-baby syndrome. 

pH - pH is an indicator of the acid or alkaline condition of water. Water with a pH less than 6.5 tends to be corrosive, while water with a pH greater than 8.5 tends to be alkaline. A pH of less than 4.5 dissolves metals such as copper and lead, a real health concern, and may affect the efficiency of water treatment units. 

Total Dissolved Solids - The total dissolved solids (TDS) is a comprehensive indicator in routine water testing. An increase in the TDS concentration indicates an increase in one or more compounds. If water test records indicate that the TDS concentration has changed, further tests are required to identify the substance(s) causing the change. 

A significant change in the TDS concentration may result from several practices. Mining activities, heavily salted roadways or unprotected salt storages can lead to increased TDS concentrations in nearby water supplies. 

Improperly lined landfills, junk yards, industrial activities, or chemical spill also could cause an increase in the TDS concentration. 

Nuisance Contaminants

Many of the substances that stain fixtures, color the water, create unusual tastes or odors are not health hazards. These nuisance chemicals may make water unpleasant to drink or prevent soap from lathering the way we are accustomed to but no harm will come from drinking these waters. Common nuisance chemicals such as various forms of calcium, chlorine, iron, magnesium, and sulfur can be removed or treated to improve the aesthetics of the water. 

Hard water is a common problem that makes it difficult to produce suds or rinse out soap. It is also responsible for the hard mineral deposits commonly referred to as milkstone or lime scale. The "hardness" of the water is mainly dissolved calcium and magnesium bicarbonates. The hard deposits left is caused by these minerals precipitating out of solution. 

Hydrogen sulfide, a dissolved gas, dissipates when exposed to air with a distinctive, rotten egg odor. Because the gas escapes from water very quickly; measurements of hydrogen sulfide concentrations must be made immediately. 

Iron stains laundry and fixtures; causes a bitter, metallic taste; and can leave a red-brown sediment. 

Iron bacteria is a nuisance bacteria that feeds on iron in the water or in the pipes. It can create a gelatinous mass capable of clogging pipes, but again, is not harmful to water consumers. A water test is not needed to identify iron bacteria because they form a very obvious slime on the inside of pipes and fixtures. A reddish brown slime on the inside of a toilet tank or where water stands for several days identifies the problem. Differentiating between slime and stains that result from oxidation of iron in the water is important when treating the problem. 

Water Sampling

Water should be sampled when the supply is most susceptible to contamination, usually after spring thaw or heavy rainfall. It's recommended to sample both before and after water goes through any treatment equipment to assure that the device(s) is working properly. The proper collection, handling, and preservation of a water sample is crucial for an accurate water test. One of the best ways to preserve water is with refrigeration, depending on which tests are being done. Always contact the laboratory before sampling. They will provide clean water sample bottles, information on how much water they need to run the tests, what type of container to use, what preservation methods to use, and how soon after sampling do they need to have the water in their hands. Only use a certified laboratory recognized and licensed by the State of New York. Call the Department of Health for a listing of certified labs. 

Treating Your Water

There are two ways of treating water for consumption - disinfection and filtration. Disinfection controls biological contaminants by killing or rendering the organism inactive. Filtration eliminates particulate, chemical and biological contaminants by removing them from the water. Many home systems use both to ensure potable water. Following is a brief discussion of the major treatment devices used. Table 8-4 lists identified contaminants and possible treatment methods. Table 8-5 is a more comprehensive listing of treatment devices and the problems they address. 

Failed Bacteria Tests

When a water sample comes back with greater than 1 coliform colony per 100 ml of water the Department of Health recommends: 

  • Perform Sanitary Survey - Search for and correct all sources of pollution.
  • Shock Chlorinate - using liquid chlorine bleach.
  • Resample - After you are sure all chlorine is gone, resample the well, using a certified laboratory and use sanitized bottles from the lab.

Note: Lake water samples are inherently susceptible to bacteria contamination and shock chlorination is not effective. All sources of water from surface waters should be continuously disinfected by an approved water disinfection system (chlorination, U.V., distillation, ozonization, etc...). 

Shock treatment is most easily achieved by pouring enough household liquid bleach into the well, cistern, holding tank, or other structure to disinfect the water. The general rule is 1 cup of bleach per 100 gallons of water to be treated. Simply pour in 2 quarts of bleach for wells with up to 100 ft of water and one gallon of bleach for those with over 100 ft of water

Pour the chlorine into the structure to be disinfected. After mixing, open ALL taps and outlets, including washing machines and dishwashers, and let run until the water issuing forth has a strong chlorine odor. Then close all the taps and allow the chlorine solution to remain in the piping system for at least 8 hours. 

Recirculating the water back to the well or reservoir with a hose, for example, insures good mixing and affords a means of washing down the walls of the structure with the chlorinated water. After the 8 hours, open all the taps and flush the system thoroughly until the water is reasonably free of the taste and odor of chlorine. Assuming that the source of pollution had been identified and removed, the system should be completely disinfected. 

If it ever becomes necessary to use water from a source of unknown sanitary quality, all drinking water and water used for cooking, cleaning food and dishes needs to be treated. Two suggested ways to treat water are boiling and chlorine bleach. 

Boiling: Water may be made safe for drinking purposed by bringing the water to a rolling boil for five minutes. The resulting "flat" taste may be removed by pouring the water from one clean container to another several times.

Liquid Bleach: Add 8 drops of a chlorine bleach for every one gallon of water. After mixing, let the solution stand for at least 30 minutes before consuming. "Clorox", and other commonly available laundry bleaches containing 5% chlorine by weight may be used.

Disinfection should not be attempted on dirty or discolored water except in an emergency. The particles in dirty water can interfere with disinfection, preventing adequate treatment. If dirt is present, first let the water stand, then pour off and treat the clear water or filter before disinfection. Water from an approved source (i.e.. commercially bottled water or water from a public water system) should be used until the contaminant is removed, steps are taken to prevent further contamination, and the water is analyzed and is proven safe. 

Water Disinfection

The major water disinfection options include: chlorination, ultraviolet radiation and ozone. Each has advantages and limitations. All are intended for use only on clean, clear water. 


Chlorination is the oldest method of continuous disinfection for public water supplies. Disinfection by chlorination has been studied extensively, and there is a lot of experience upon which to draw. Chlorination is the standard by which other disinfection procedures are judged. 

Chlorine is a strong oxidizing agent. It is cheap, reliable, easy to use and monitor - and it is safe. A dose of chlorine large enough to be harmful smells too bad to drink. Chlorine is also easy to remove. Exposure to the atmosphere, heating, or filtering through activated carbon will remove chlorine from water. 

Chlorination may be done in many ways. It may be injected into the water supply stream for continuous disinfection or added to a known volume of water as a batch treatment procedure. Chlorine is also used for sanitizing wells and plumbing systems whenever a new system is put into operation or when an existing system has been exposed to contamination. 

Chlorine does have some drawbacks. It requires time to react and organisms vary in their resistance to chlorine. Most bacteria are relatively easy to kill. Viruses as a rule are more difficult to kill and many cysts and worms are relatively unaffected. Chlorine also attacks reduced forms of iron, manganese and organic matter which is common in many water supplies. If the chlorine is consumed in reacting with these elements, it is not available to attack the pathogens for which it was intended. Also, the reaction of chlorine with organic matter may produce trihalomethanes (THM) which are known carcinogens. Finally, many people do not like the taste or smell of chlorine in the water. 

The amount of chlorine should be checked by residual tests. A water source that requires routine disinfection requires routine checking. Simple, do-it-yourself test kits are available and the homeowner should test periodically. Frequent testing should be done initially to gain experience with the treatment equipment and the test procedure. After a time, weekly or bi-weekly testing should be enough. Testing is the only way to be sure the treatment procedure is working. A residual of 0.1 to 0.5 ppm at the point of use is acceptable and indicates that everything is working. 

Ultraviolet Radiation

Ultraviolet (UV) light has long been known to have germicidal properties, but equipment using this principle in private water systems is quite new. Common low-pressure mercury arc lamps produce a high percentage of their ultraviolet light in the spectral range of 260 nanometers (a nanometer is one billionth of a meter), which is from just below visible light. Most microorganisms are affected by radiation between 200 and 300 nanometers. UV does not kill Giardia lamblia cysts or Cryptosporidium parvum oocysts, which must be removed by filtration or boiling. Nor is UV recommended for water exceeding 1000 total coliform or 100 fecal coliform per 100 ml of water. 

Ultraviolet treatment has the advantage of adding nothing to the water and not requiring the addition of treatment materials as long as the lamp is maintained in good operating condition. The major disadvantage is that there is no residual for treatment beyond the device. If contamination occurs after treatment, another disinfection method such as chlorination will have to be used to sanitize the system and treat the water. Some pathogens deactivated by UV light may be reactivated when exposed to oxygen as there is no residual to counteract recontamination. Water or reconstituted drinks stored for extended times in the refrigerator should be boiled or treated with a small amount of disinfectant if UV is the primary disinfection process. 

For UV radiation to work the light must come in contact with the organism. Therefore, all surfaces that the light must pass through need to be kept clean. The UV bulbs do not burn out - they gradually lose power with use. Replacing the bulb at least once per year will help ensure proper treatment of the water. If the system is shut down for several days or longer, any water left in the system should be drained and the entire plumbing system flushed. 

Ozone Treatment

Ozone, like chlorine, is a strong oxidizing agent and is used in much the same manner. The major difference is that ozone is unstable so it cannot be produced and transported to the point of use. It must be generated at the point of use. Ozone, a triatomic form of oxygen, is the product smelled near an electric spark or lightening strike. For water treatment, ozone is produced by an electrical corona discharge or ultraviolet irradiation of dry air or oxygen. 

Ozone is unstable and extremely active as a disinfectant. The required contact time is so short that it is not a consideration in the design. Municipal systems in Europe have used the procedure for many years but only recently has the technology been applied to public systems in the United States. Now small units are available for the homeowner. The benefits are the strength of the disinfection and the lack of potentially harmful by-products like trihalomethanes (THM). 

Like chlorine, ozone may not kill cysts and some other large organisms, so these should be eliminated by filtration or other procedures prior to treatment. 

Ozone has an active residual effect measured in minutes while the residual for chlorine is measured in hours. This lack of long residual is probably the greatest drawback for use in public water systems in the United States.

Keuka Lake - Clouds & Sailboat


Founded in 1956, the Keuka Lake Association, with over 1700 members, provides a unified voice for those who love Keuka Lake. Our mission is to preserve and protect Keuka Lake and its natural beauty for future generations.

Keuka Lake Association is a 501(c) (3) organization (a non-profit tax exempt organization under IRS rules). This distinction is defined by our service to the public and how we are mission-driven as opposed to profit-driven.

Gifts, donations and membership dues paid to our organization are used in direct service to the overall mission to preserve and protect Keuka Lake. Membership dues, donations and gifts are tax deductible to the extent permitted by law. Consult your professional tax preparer if you have specific tax related questions.