Private Well Owners Urged To Take Water Precautions
(Santa Fe, NM) —Private domestic water well owners inundated by floodwater caused by recent heavy rain are being advised to take precautions. Flood water can be tainted by sewage leaked by flooded septic systems, and the floodwater can contaminate water wells. For private domestic water well users whose wells have been inundated by the floodwater, the New Mexico Environment Department (NMED) recommends the following actions:
1. The well water should be vigorously boiled for 5 minutes before use for drinking, cooking, dishwashing or bathing, until a well water test shows no contamination.
2. The water well should be disinfected with the procedure detailed below.
3. After the disinfection procedure is complete, the well water should be tested for total and fecal coliform bacteria. Laboratories certified by NMED to test drinking water for bacteria are listed here http://www.nmenv.state.nm.us/dwb/Labs/documents/Certifiedlablistforweb_062013.pdf
4. The well can be returned to normal domestic use after the test results show no bacterial contamination.
· Unscented household bleach containing 5.25% chlorine can be used to disinfect wells. One gallon of bleach will treat up to an 8-inch diameter well containing 100 feet of water.
· Avoid direct skin contact with bleach. Wear rubber gloves and goggles when handling bleach. If skin or eye contact occurs, flush immediately with clean water.
· Mix 2 quarts of bleach in 10 gallons of water; pour into well.
· Connect a garden hose to a nearby faucet and wash down the inside of the well.
· Open each faucet and let water run until a strong chlorine odor is detected, then turn it off. Do this for each indoor and outdoor faucet and hydrant. Drain the water heater and let it refill with chlorinated water. If a strong odor is not detected at all outlets, add more chlorine to the well. Also flush the toilets.
· Mix an additional 2 quarts of bleach in 10 gallons of water. Pour it into the well without pumping.
· Allow chlorinated water to stand in the well and pipes for at least 8 hours (preferably 12 to 24 hours).
· Run water from outdoor faucets to waste (away from desirable vegetation) until the chlorine odor is slight or not detected at each faucet. Then run indoor faucets until there is no chlorine odor. Minimize the amount of chlorinated water flowing into the septic tank.
Some chlorine may persist in the system for 7-10 days. Water with a slight chlorine smell should be usable for most purposes including drinking.
From the EPA
What to Do After the Flood
Drilled, driven or bored wells are best disinfected by a well or pump contractor, because it is difficult for the private owner to thoroughly disinfect these wells.
If you suspect that your well may be contaminated, contact your local or state health department or agriculture extension agent for specific advice on disinfecting your well. The suggestions below are intended to supplement flood precautions issued by State and local health authorities.
Well and Pump Inspection
Flood Conditions at the Well - Swiftly moving flood water can carry large debris that could loosen well hardware, dislodge well construction materials or distort casing. Coarse sediment
in the flood waters could erode pump components. If the well is not tightly capped, sediment and flood water could enter the well and contaminate it. Wells that are more than 10 years old or less than 50 feet deep are likely to be contaminated, even if there is no apparent damage. Floods may cause some wells to collapse.
Electrical System - After flood waters have receded and the pump and electrical system have dried, do not turn on the equipment until the wiring system has been checked by a qualified electrician, well contractor, or pump contractor. If the pump’s control box was submerged during the flood all electrical components must be dry before electrical service can be restored. Get assistance in turning the pump on from a well or pump contractor.
Pump Operation - All pumps and their electrical components can be damaged by sediment and flood water. The pump including the valves and gears will need to be cleaned of silt and sand. If pumps are not cleaned and properly lubricated they can burn out. Get assistance from a well or pump contractor who will be able to clean, repair or maintain different types of pumps.
DO NOT TURN ON THE PUMP There is danger of electrical shock and damage to your well or pump if they have been flooded
DO NOT WASH WITH WELL WATER People drinking or washing with water from a private well that has been flooded will risk getting sick.
Emergency Disinfection of Wells that have been Flooded
Before Disinfection: Check the condition of your well. Make sure there is no exposed or damaged wiring. If you notice any damage, call a professional before the disinfection process.
If your water is muddy or cloudy, run the water from an outside spigot with a hose attached until the water becomes clear and free of sediments.
Determine what type of well you have and how to pour the bleach into the well. Some wells have a sanitary seal with either an air vent or a plug that can be removed (a). If it is a bored or dug well, the entire cover can be lifted off to provide a space for pouring the bleach into the well
• One gallon of non-scent- ed household liquid bleach; • rubber gloves;
• eye protection;
• old clothes; and • a funnel.
Take the gallon of bleach and funnel (if needed) and carefully pour the bleach down into the well casing.
After the bleach has been added, run water from an outside
hose into the well casing until you smell chlorine coming from the hose. Then turn off the outside hose.
Turn on all cold water faucets, inside and outside of house, until the chlorine odor is detected in each faucet, then shut them all off. If you have a water treat- ment system, switch it to bypass before turning on the indoor faucets.
Wait 6 to 24 hours before turning the faucets back on. It is important not to drink, cook, bathe or wash with this water during the time period --- it contains high amounts of chlorine.
Once the waiting period is up, turn on an outside spigot with hose attached and run the water into a safe area where it will not disturb plants, lakes, streams or septic tanks. Run the water until there is no longer a chlorine odor. Turn the water off.
The system should now be disinfected, and you can now use the water.
Have your water tested for bacteria 7 to 10 days after disinfection.
CAUTION: Because of the extensive flood area and the speed and direction of ground water flow, your well may not be a safe source of water for many months after the flood. The well can become contaminated with bacteria or other contaminants. Waste water from malfunction- ing septic tanks or chemicals seeping into the ground can contaminate the ground water even after the water was tested and found to be safe. It will be necessary to take long range precautions, including repeated testing, to protect the safety of drinking water.
Sampling and Testing the Well Water
Contact the local health department to have well water sampled and tested for contamination. Or, call your state laboratory certification officer to find a certified lab near you. You can get this number from the Safe Drinking Water Hotline (1-800-426-4791).
If the health department issues sterile bottles for the private well owner to collect water samples, fol- low all instructions for the use of these bottles.
After the pump is back in operation, the health department should sample and test the water at regular intervals.
CONCERNS AND ADVISORIES
If in doubt about the well water supply, follow health department drinking and bathing advisories.
Remember that there is a danger of electrical shock from any electrical device that has been flooded; consult a certified electrician. Rubber boots and gloves are not adequate protection from electric shock.
Well disinfection will not provide protection from pesticides, heavy metals and other types of non-biological contamination. If such contamination is suspected, due to the nearness of these contaminant sources, special treatment is required.
Information on home water treatment units (also called point-of-use and point-of-entry units) is available from U.S. EPA by phoning the Safe Drinking Water Hotline (1-800-426-4791).
If you observe chemical containers (including barrels and drums) that have moved to your property, call your state or county health department or the Superfund Hotline (1-800-424-9346).
For information on long-term water quality conditions in the area, consult the state or county health department.
Well owners may have information about the construction, or testing of their well and this information will be helpful to the health department in determining water quality conditions.
Septic systems should not be used immediately after floods. Drain fields will not work until underground water has receded. Septic lines may have broken during the flood.
OFFICE OF WATER (4606 M) www.epa.gov/safewater EPA 816-F-05-021 AUGUST 2005
Septic Systems—What to Do after the Flood
Where can I find information on my septic system?
Please contact your local health department for additional advice and assistance. For more information on onsite/decentralized wastewater systems, call the National Environmental Services Center at (800) 624-8301 or visit their website at www.nesc.wvu.edu.
Do I pump my tank during flooded or saturated drainfield conditions?
No! At best, pumping the tank is only a temporary solution. Under worst conditions, pumping it out could cause the tank to try to float out of the ground and may damage the inlet and outlet pipes. The best solution is to plug all drains in the basement and drastically reduce water use in the house.
What if my septic system has been used to dispose wastewater from my business (either a home–based or small business)?
In addition to raw sewage, small businesses may use their septic system to dispose of wastewater containing chemicals. If your septic system that receives chemicals backs up into a basement or drain field take extra precautions to prevent skin, eye and inhalation contact. The proper clean-up depends of what chemicals are found in the wastewater. Contact your State or EPA for specific clean-up information.
What do I do with my septic system after the flood?
Once floodwaters have receded, there are several things homeowners should remember:
• Do not drink well water until it is tested. Contact your local health department.
• Do not use the sewage system until water in the soil absorption field is lower than the water level around the house.
• Have your septic tank professionally inspected and serviced if you suspect damage. Signs of damage include settling or an inability to accept water. Most septic tanks are not damaged by flooding since they are below ground and completely covered. However, septic tanks and pump chambers can fill with silt and debris, and must be professionally cleaned. If the soil absorption field is clogged with silt, a new system may have to be installed.
• Only trained specialists should clean or repair septic tanks because tanks may contain dangerous gases. Contact your health department for a list of septic system contractors who work in your area.
• If sewage has backed up into the basement, clean the area and disinfect the floor. Use a chlorine solution of a half cup of chlorine bleach to each gallon of water to disinfect the area thoroughly.
• Pump the septic system as soon as possible after the flood. Be sure to pump both the tank and lift station. This will remove silt and debris that may have washed into the system. Do not pump the tank during flooded or saturated drainfield conditions. At best, pumping the tank is only a temporary solution. Under worst conditions, pumping it out could cause the tank to try to float out of the ground and may damage the inlet and outlet pipes.
• Do not compact the soil over the soil absorption field by driving or operating equipment in the area. Saturated soil is especially susceptible to compaction, which can reduce the soil absorption field’s ability to treat wastewater and lead to system failure.
• Examine all electrical connections for damage before restoring electricity.
• Be sure the septic tank’s manhole cover is secure and that inspection ports have not been blocked or damaged.
• Check the vegetation over your septic tank and soil absorption field. Repair erosion damage and sod or reseed areas as necessary to provide turf grass cover.
Remember: Whenever the water table is high or your sewage system is threatened by flooding there is a risk that sewage will back up into your home. The only way to prevent this backup is to relieve pressure on the system by using it less.
1. What are some suggestions offered by experts for homeowners with flooded septic systems?
2. Use common sense. If possible, don’t use the system if the soil is saturated and flooded. The wastewater will not be treated and will become a source of pollution. Conserve water as much as possible while the system restores itself and the water table fails.
3. Prevent silt from entering septic systems that have pump chambers. When the pump chambers are flooded, silt has a tendency to settle in the chambers and will clog the drainfield if it is not removed.
4. Do not open the septic tank for pumping while the soil is still saturated. Mud and silt may enter the tank and end up in the drainfield. Furthermore, pumping out a tank that is in saturated soil may cause it to “pop out” of the ground. (Likewise, recently installed systems may “pop out” of the ground more readily than older systems because the soil has not had enough time to settle and compact.)
5. Do not dig into the tank or drainfield area while the soil is still wet or flooded. Try to avoid any work on or around the disposal field with heavy machinery while the soil is still wet. These activities will ruin the soil conductivity.
6. Flooding of the septic tank will have lifted the floating crust of fats and grease in the septic tank. Some of this scum may have floated and/or partially plugged the outlet tee. If the septic system backs up into the house check the tank first for outlet blockage. Clean up any floodwater in the house without dumping it into the sink or toilet and allow enough time for the water to recede. Floodwaters from the house that are passed through or pumped through the septic tank will cause higher flows through the system. This may cause solids to transfer from the septic tank to the drainfield and will cause clogging.
7. Locate any electrical or mechanical devices the system may have that could be flooded to avoid contact with them until they are dry and clean.
8. Aerobic plants, upflow filters, trickling filters, and other media filters have a tendency to clog due to mud and sediment. These systems will need to be washed and raked.