• Rideau Valley Conservation Authority
• Mississippi Valley Conservation Authority 
• MVCA's External Flood Emergency Preparedness Manual

Recent heavy rains across the province have swollen lakes and rivers across several watersheds and resulted in water ponding on many properties. Some properties have been affected by flooding.

Flood water and water ponding around wells and septic systems can affect the safety of your drinking water and how your septic system works. The Leeds Grenville and Lanark Health Unit is advising those whose wells are directly affected by these conditions to boil their water for one minute at a rolling boil before drinking the water. Have your well water tested for bacteria.

If your septic system has been affected, limit water usage by taking quick showers rather than baths, avoid using the dishwasher, garbage disposal and washing machine and flush your toilets only when necessary. Ensure your basement sump pump is not going into the septic system.

Do not pump out your septic tank when the soil around the tank or the leaching bed is still saturated with water. High ground water levels may cause an empty septic tank to float and break out of the ground, and damage the tank and connecting plumbing.

The following tips will help protect your family during flooding events:

• Keep your family safe by keeping family members and pets away from and out of the flood water.
• DO NOT enter areas where electrical systems have been affected by flood water as you may be electrocuted. Always wait for clearance from the electrical authority before entering these areas.
• Building materials, clothing and furniture exposed to flood waters are likely contaminated with sewage and can support the growth of mold. Some items can be cleaned and disinfected; others may need to be thrown out.
• Ask for professional advice during clean up. If you try to save and clean items on your own, wear protective clothing, a mask and gloves.

Spring Flooding

Thawing of snow and ice combined with spring rains may cause localized flooding on some properties.  Flood water and water ponding around wells can affect the safety of your drinking water. The Leeds, Grenville and Lanark Health Unit is advising those whose wells are directly affected by these conditions to boil their water for one minute at a rolling boil before drinking the water, or use an alternate safe source until you test your water and confirm that it is safe to drink.

A few tips to keep in mind if your property is prone to flooding:

• Monitor weather and take warnings seriously.
• Monitor your local conservation authority website and alerts for localized flooding risks.
• Ensure drainage ditches, etc. around your home are clear and can function during periods of heavy rain.
• Label the shut off valves and the direction to turn off the gas, water, power, etc. If you must leave your home due to rising flood waters, turn off the power, gas, etc.
• Maintain your home to keep water out.
• Move items likely to be affected by a flood water to higher areas where possible.
• Ensure chemicals, cleaners; gas cans, etc. are stored in such a manner as not to contaminate flood water.
• Ensure you have a supply of fuel for generators and pumps in the event of power outage. Store fuel in a manner so as not to contaminate flood water.
• Have an emergency kit stocked; be sure to include important documents, cash, safe drinking water, food and medication.

Visit the Well Water Sampling for drinking water information including:  where you can pick up and drop off your free water bottle samples; how to take a sample; how to disinfect your well (if required). For more information, call the Leeds, Grenville & Lanark District Health Unit at  1-800-660-5853.

After Flooding

After flooding, well owners should take actions to:

• make their water supplies safe for consumption; and
• protect the groundwater resource used as a source of drinking water.

When a water supply well has been affected by flood waters, the water within a well may be contaminated with waterborne pathogens (germs) that can cause serious illness in humans and pets. The water in the well can also be contaminated by debris, fuel oil or other chemical products released during the flood.

During flooding, the ground around the well may also erode, possibly creating unsafe conditions or a pathway for surface water and contaminants to enter the well. In other cases, the electrical wires attached to the pump in a well may be damaged risking
electrocution. Therefore, well owners should exercise extreme caution approaching their wells, especially older, large diameter dug wells after a flood.

If a well owner believes that the well has been contaminated by flood water, the well owner should discontinue using the water in the well for drinking and cooking purposes and use potable water from another source.

Under the Wells Regulation [R.R.O. 1990, Regulation 903 (Wells) as amended made under the Ontario Water Resources Act, R.S.O. 1990, c. O. 40]:

• the well owner must maintain the well to prevent the entry of surface water and other foreign materials.
• if laboratory analysis of water samples from the well show the well is producing water that is not potable, then the well owner must contact the local Medical Officer of Health (MOH) and follow his or her advice or immediately abandon the well. As an alternative to contacting the MOH, the well owner could contact the Director appointed under the Wells Regulation at 1-888-396-9355 (WELL) for written consent not to abandon the well.

To bring a well back into service safely, a well owner should consider contacting:

• a qualified registered professional (e.g. professional engineer or professional geoscientist) or a licensed well driller to evaluate and service a drilled well;
• a qualified registered professional or a licensed well digger to evaluate and service a dug well;
• a licensed pump installer and, if necessary a certified electrician, to evaluate and service the well pump.

Note - A residential private well owner can work on and disinfect his or her own well. However, there are some safety considerations when working on a well and many technical steps needed to properly clean and disinfect a well. Therefore, the well owner should consider retaining the services of a qualified professional or qualified technician as noted above.

If the well structure, pump and surrounding ground surface have been repaired or are deemed sound, the water in the well should be pumped and disinfected by a licensed well technician as outlined in Chapter 8: Well Disinfection of the Water Supply Wells – Requirements and Best Management Practices manual published by the Ministry of the Environment and Climate Change, revised 2015.

The Well Disinfection chapter of the manual provides the following steps to properly disinfect a well:

• Initial steps which include:
  • following sanitary practices
  • removing any debris from a well
• Thorough flushing of the well
• Treatment with a properly prepared chlorine solution, i.e. “shock” chlorination
• Discharge of heavily chlorinated water from the well and the plumbing
• Collection and analysis of water samples for indicator bacterial parameters

The Well Disinfection chapter of the manual is available here.

A synopsis of the Well Disinfection chapter for interested well owners is provided in the Wells Regulation – Well Disinfection 2011 technical bulletin and is available the government of Ontario's website.

Information on proper well maintenance, and other well related topics, is available on the Ontario.ca website.

What steps should I take if my septic system is flooded?

• It is strongly recommended that the system should not be used while the septic drain field or tanks are covered with water. The sewage system should not be used until the water in the septic drain field is below the distribution pipes.
• If the system must be used, conserve water as much as possible while the system attempts to restore itself as the ground water table falls.
• Flood water may be contaminated with sewage. Protect yourself by wearing protective equipment such as gloves, protective eyewear, a face mask and rubber boots. Be sure to wash your hands frequently with soap and water.
• Do not pump your septic tank. Pumping out a septic tank that is sitting in saturated soil may cause it to “pop out” of the ground. Newer systems are more likely to pop out than older systems because the soil may not have completely settled and compacted around the septic tank.
• Try to avoid using any heavy machinery near the septic drain field or tanks in a saturated state, as they are especially vulnerable to damage under flooded conditions.
• If sewage has backed up into a basement, clean the area and disinfect the floor. Use a chlorine solution of a half cup of chlorine bleach to a gallon of water when mopping the floor.
• If you have a ground water well, do not drink the water until water testing proves it to be safe for consumption.

For more information, please contact Eric Kohlsmith, Septic Inspector, Mississippi Rideau Septic System Office at 613 253 0006 ext. 256 or by email at This email address is being protected from spambots. You need JavaScript enabled to view it.