Well water and health: Well safety during and after emergencies

What to do when flooding, droughts or other events affect the quality of your well water.

On this page

• Well safety
• Floods
• Droughts
• Fires
• Power outages
• Freezing

Well safety

Extreme weather, floods, fire and drought are examples of events that can damage your well and contaminate your water. The water can become contaminated by microorganisms or chemicals without any noticeable change in taste, odour or clarity.

After an emergency, it's important to make sure your well water is safe before using it again.

Have a back-up water supply ready in case of emergencies. If your well is contaminated or damaged, it may take a few days before you can safely use your well water again.

For specific advice, contact your local public health unit or provincial or territorial drinking water authority when needed.

Floods

During a flood, don't use well water for:

• drinking
• cooking
• bathing
• showering
• brushing teeth

Flood waters can introduce contaminants by completely submerging your well head or pumping system. You'll need to use a safe, alternative water supply until you can determine that your water is safe to use.

After a flood, do not turn on the well pump. There's a risk of electrical shock due to wet or damaged equipment. Hire a licensed well contractor to inspect your well and its wiring before use.

Test your well water for microbial contaminants and shock disinfect if needed.

How to treat your well

You should also test for chemical contaminants that are of concern in your area and that could enter your well through flood waters. For example, these contaminants could come from nearby fuel, pesticide or chemical storage facilities. Contact your local public health unit or drinking water authorities for advice on testing for chemicals.

Check your well for damage as flood waters may carry debris that can damage well components. Repair or replace any damaged components as soon as possible.

If repeated flooding is an issue, consider:

• extending your well casing
• installing a flood-proof cap with an extended vent
• moving your well

Droughts

If you have a shallow well or live in an area that is prone to drought, you might experience water shortages.

To avoid running out of water during times of drought:

• conserve water
• install a storage tank
• reduce your pumping rate
• use alternative water sources to lower demand

Don't over-pump your well because that can lead to problems like sediment plugging. This may cause premature well failure as particles of sand, silt, clay or other ground material can clog the well.

If your well depressurizes due to a water shortage, you'll need to test and shock disinfect your well.

If water shortages are an ongoing problem, you may have to find a different water supply. This could include:

• drilling another deeper well
• using water from a municipal source
• using treated surface water

Learn more:

• Building a well
• Testing your well water
• Treating your well water

Fires

If a fire or wildfire has occurred close to your well or property, do not use your well water. It may be contaminated by:

• fire-suppressants
• ashes from burned material
• toxic chemicals from melted well parts
• contaminants released from:
  • stored fuel
  • heating oil tanks
  • damaged septic systems
• chemicals released by the combustion of soil and wood

Before using your well water, look for any sources of contamination as soon as possible. Check for damage to your:

• septic system
• home fuel or oil storage tank
• well, water components or equipment

Well, water components or equipment

Check well components and above or below ground piping by looking for:

• leaks
• charring or melting
• the smell of burnt plastic
• damage to the well casing or cap
• damage to electrical wires, conduits and connectors

Contact a licensed water well contractor to assess the damage and make necessary repairs if your well, water components or equipment (for example, pipes or a pump) were damaged by fire.

Test your well for volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs) and other local contaminants of concern if:

• there's a lot of fire damage on or surrounding your property
• there's a lot of damage to your well components or equipment
• your well components are made of materials such as polyvinyl chloride (PVC), high density polyethylene (HDPE) or rubber

Septic system

Check your septic system by looking for:

• damaged or melting components such as:
  • piping
  • vent pipes
  • drain field inspection ports
• damage to the ground where the drain field is located
• damage to where the septic system pipe enters the home

If your septic system was damaged by fire:

• test your well water for E. coli and total coliformbacteria
• contact a septic system professional to assess the damage and make the necessary repairs

Home fuel or oil storage tank

If you have a home fuel or oil storage tank, make sure it hasn't spilled or leaked as this could contaminate your water. To clean up visible spills, place an absorbent material like cat litter on top. This will absorb the fluid and help prevent it from seeping into the groundwater. If safe, scoop any absorbed contaminant into a metal container.

Report large spills (such as more than 100 liters) to your local authorities. It's a good idea to have a licensed technician check the tank, line and appliances for possible damage, such as:

• dents
• swelling
• discoloration
• chipped paint

After inspecting your well and property and correcting any issues, confirm your well water is safe to use by:

• letting the water run for a few minutes to get rid of the stagnant water from the lines
• testing for microbial and chemical contaminants, particularly hydrocarbons

Contact your local public health unit or drinking water authorities for more information about your specific situation.

Continue to test your water quality over time. Any changes to the surrounding area as a result of a fire or wildfire may have long term impacts on your water quality.

Test your well water

Power outages

Power outages can disrupt your water supply. Depending on the cause, power outages can last hours, days or even weeks.

Normally, an electric water pump draws groundwater from the well and maintains the water pressure in your home. This pressure forms a physical barrier that stops contaminants from entering the water system.

During a power outage, do not:

• open faucets
• take showers
• flush toilets

Your water system may have several litres of water in storage. However, using the water while the power is out depressurizes the system and increases the chances of contamination.

Make sure that you have your well water tested before using it if:

• your water system loses all of its pressure
• no water comes out of the faucets

Once power has been restored, flush the lines by letting the water run for a few minutes to get rid of the stagnant water. If you have a treatment system for your well, make sure it's running properly. You can also contact the manufacturer about any other cleaning steps you may need for your specific system.

Test your well water

Freezing

During the winter, extreme low temperatures may cause parts of your water system to freeze. This could leave you with no water.

To prevent freezing, make sure all water lines are:

• insulated and heated or
• buried below the local frost level or
• located within a heated space like a pump house

If you're worried a pipe will freeze, open the faucet served by the exposed pipe and let it drip.

If your water pipes freeze, use hot air or steam to thaw them. If the water in your well has frozen, get advice from a licensed well contractor or a plumber before using it again.