Well Contamination

Properly constructed and maintained water wells can provide many years of trouble-free service, but like any other mechanical devices, wells will eventually deteriorate or become damaged, and allow surface contaminants to enter the water. In addition, some groundwater can contain one or more chemical substances in concentrations above state health limits. Public water systems are tested regularly for a variety of contaminants, but if you have a private well, regular testing is up to you. Here are some recommendations that you can follow to assure that your well water is safe. First, make sure that your well is located and constructed properly.

All water wells constructed in Florida must meet the location and construction requirements of the Florida Well Code. Wells can provide safe water for many years, but as wells age, they will deteriorate and eventually lose their ability to keep contaminants out of the water. If your well is old, or has not been inspected for many years, contact a licensed well contractor and have the well inspected. If your well has outlived its useful life, it should be properly sealed and replaced with a modern, safe well.

When constructing additions to your house, adding new buildings, or making changes to septic systems or other contamination sources, be sure to maintain the required separation distances to your well. When landscaping, keep the top of the well at least one foot above the ground surface. Make sure that the well cap is undamaged and securely attached to the well casing, and that any connections to the well stay watertight. Keep hazardous chemicals like paint, fertilizer, pesticides, fuels, and motor oil away from your well. Seal any unused wells on your property to protect your groundwater from contamination (note: under Florida law, only a licensed well contractor can seal a well).

Water that has become contaminated by human or animal wastes can transmit a variety of infectious diseases, including dysentery, salmonellosis, hepatitis, and giardiasis. Symptoms vary, but nausea, vomiting, and diarrhea, with or without fever, are most common. To assess bacterial safety, drinking water is tested for a group of indicator bacteria called “total coliform bacteria”. These bacteria do not usually cause disease themselves, but their presence indicates that surface contamination has found its way into the well and disease organisms may also be present. When total coliform bacteria are found in well water, the water should not be consumed without boiling, and the well should be disinfected.

Elevated levels of nitrate are often caused by run-off from barnyards or feedlots, excessive use of fertilizers, or septic systems. Wells most vulnerable to nitrate contamination include shallow wells, dug wells with non-watertight casings, and wells with damaged, leaking casing or fittings. Well water containing nitrate at levels above the state health limit should never be given to infants less than six months old, because it can cause a potentially fatal disease called "blue baby syndrome." In many cases, constructing a deeper well can reduce or eliminate a nitrate problem.

Pipes and other components of the household plumbing system (faucets, valves, or fittings) may contain lead. If they do, lead may slowly dissolve into the water. The longer the water stands idle in the pipes, the higher the lead levels can become. Too much lead in the body can damage the brain, nervous system, and kidneys, and it can be especially harmful to infants and small children. To minimize your exposure to lead in your drinking water, run the water until it gets cold before using it for drinking or cooking. This will flush out most of the lead that may have accumulated in the plumbing. Also never use water from the hot water tap for drinking or cooking. The best way to get a complete picture of how much lead may be dissolving into your water is to have the water tested for lead.

Long-term consumption of arsenic above the drinking water standard may increase the risk of health problems of the skin, circulatory system, or the nervous system. Every private well should be tested at least once or twice to determine if arsenic is present in the water, and at what levels. Arsenic levels in groundwater will not usually change much over time. Long-term consumption of well water with arsenic levels above 10 micrograms per liter should be avoided. Special types of water treatment systems which are proven effective in removing arsenic from drinking water include "reverse osmosis" and "distillation" treatment systems. In addition, several promising new technologies for removing arsenic are currently under development. Contact a reputable water treatment dealer in your area for information about water treatment systems.

Testing your well water for other contaminants

Pesticides

Wells most at risk of pesticide contamination are shallow or old, located close to areas of pesticide use or storage, and located in geologically sensitive areas such as sand plains or "karst" (weathered limestone) bedrock areas. Wells that have high levels of nitrate are also more likely to have detectable levels of pesticides. If you have an old or shallow well and you live in an agricultural area, or if your well has a high level of nitrate, consider testing your well water for one or more of the pesticides used most frequently in your area.

VOCs

Volatile Organic Chemicals, or "VOCs" are common components of gasoline and other fuels, as well as products such as solvents, paints, cleaners, and degreasers. Long-term exposure to VOCs above state health limits may damage the central nervous system, liver, or kidneys, and some VOCs are known to cause cancer. If you live near a commercial or industrial area, a gas station, or a landfill, and especially if your well is old or shallow, you should consider having your water tested for VOCs.

Fluoride

If children or adolescents are drinking the well water, a test for natural levels of fluoride will give your dentist valuable information when considering fluoride supplements. A small number of wells, primarily in northeastern Minnesota, do exceed the recommended health limit for fluoride, which can cause discoloration of tooth enamel.

Your county health agency can provide testing for bacteria and nitrate, and some laboratories are certified to perform other tests. Prices vary depending on the test.