Flooded Water Wells

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Restoring Flooded Water Wells Back to Health


Restoring Flooded Water Wells Back to Health

Flooded water wells will be of concern for property owners with a private water well that may be vulnerable to seasonal flooding. Floods are the #1 natural disaster. Water wells are an essential resource for millions of private properties through-out North America.

A water well may easily become contaminated during a natural disaster and re-establishing safe water after a flood is very important.

Flooded water wells may contain flood water with bacteria and viruses absorbed from soil, organic debris, and sewage systems in addition to possible fertilizers, pesticides, and other chemical contaminants.

Often a residential water well that has been flooded can be cleaned-up and restored quickly. Most aquifers are generally a safe water source because they are naturally protected from the effects of flooding.

Even though an aquifer may be safe, if a water well is flooded, do not use it should not be used for drinking or food preparation until it has been adequately tested and if necessary treated to destroy any possible disease-causing pathogens.

Testing of flooded water wells should be ongoing over several weeks because some negative effects of flooding may not immediately apparent. Here are some of the potential water well issues that may take time to resolve after the flooding of a well.

Well Water Quality After Flooding

The cause of flooded water wells, high flood waters can result in surface water that has been contaminated by possible sources of well contamination include waste discharge to the ground, such as privy vaults (also known as an outhouse or pit toilet), cesspool (“overflow” pits), underground storage tanks, septic tanks an effluent field, stable or pig sty, manure heap, fertilizers and pesticides, runoff from urban areas, broken fuel lines, even a cemetery or landfill sites.

Even if the well head was not submerged, excessive aquifer recharge might raise water levels in aquifers dangerously high putting groundwater in contact with contaminants in the soil.

If flood waters have come in contact with your water well or your well pit, it’s possible for the water to seep down around the well casing and gain entry to a water well – the drinking water from your residential water well can quickly become contaminated, this is considered a flooded water well (Remember the Walkerton water tragedy that occurred in 2000?)

Water well flooding can happen when rising water tables reach the level of septic fields in septic systems. This is another reason it’s recommended that all water wells be tested during the wet weather season whether the wellhead has been flooded are not

If you live in a coastal area and flooded water wells may also be the result of a tidal surge, there could be a temporary increase is sodium and chloride levels. Some of the wells on the Gulf Islands of British Columbia are known to be what we call tidal wells.

Flooded Water Wells & Well Pumps

If a well has a properly fitted cap and screened vent it has probably not been affected by debris and may have just taken in a small amount of sediment and contaminated water.

However, if there is an above-ground jet pump that has been flooded, it should be disconnected, dried, cleaned and checked before restarting, it’s always recommended that a professional is brought in to assess possible damaged water well equipment.

Power outages are commonly associated with flooding or other natural disasters. If you have a back-up generator, there are some safety rules to follow before connecting your pump to a generator.


Restoring Flooded Water Wells

To avoid possible electrical problems, the well pump should be dis-connected from the power-source before connecting it to your generator. Unless the connection has been made previously, the work will require a qualified electrician, especially if it’s a three-phase pump.

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Flooded Water Wells – After the Flooding

After assessing all the equipment for possible damage and operating issues, it’ll be time to restart the well pump, the water well should be disinfected, recirculated, and purged. Depending on the situation. you may want to test the well prior to determine whether the well has been affected by flooding.

Purging & Disinfection of Flooded Water Wells

First, flooded wells should be pumped down to remove water that may have entered during flooding. This will allow the chlorine disinfection process to work more efficiently.

It’s best to purge a water well by connecting a garden hose to the pressure tank or another outside hose-bib, there are many variables when pumping a well, it may take less than an hour to much longer. It will depend on the well depth, yield of the well, and capacity of the well pump.

It will be important to safely pump the well until the water runs clear, remember it’s very important to not over-pump the well. Water samples should be taken at the beginning and end of the well pumping process to be tested for bacteria. If you suspect oil or gas may have entered your well, contact a local well water professional to service the well professionally.

Testing Flooded Water Wells

While homeowners can disinfect a water well for bacterial contamination, the most common problem for flooded wells, they should also have a more comprehensive drinking water test down to ensure that your water quality has returned to normal.

Home bacteria test kits are available at most hardware stores and can give a result in about 24 hours. Most water experts agree that well water should be tested by a certified laboratory and cleared before consuming any water. Home testing kits should not be completely relied on.

As an additional precaution, iodine tablets are approved for drinking water disinfection should also be used for a few weeks after the flood to ensure further that your water is safe after purging and disinfection if there is not a reliable method of disinfection in place.

It may be best to not consume the water until it’s once again deemed safe, bottled water may be the best short term alternative if it available, boiling is another option.

Disinfecting Flooded Water Wells

Disinfection is recommended for any well that may have been impacted by flooding. Well disinfection is used to inactivate or control bacteria populations in a well and the distribution system.

There are several methods used to disinfect water wells including simple chlorination, shock chlorination or bulk displacement and a procedure for wells that are difficult to disinfect. 

Water Well Safety Precautions To Take

Chlorine is very volatile, it’s dangerous to work with chlorine within confined areas where vapors can accumulate such as well houses, pits, and crawl spaces.

Caution should be used when working in these situations and it’s highly recommended that water well disinfection is conducted by a professional water well expert when possible, when dealing with water wells there are many variables and seldom an exact process.

Water well flooding is no joke. It can severely impact the quality and safety of a properties water supply. By quickly taking the appropriate steps, you can mitigate the risks and return a water well back to good health soon after flooding or other natural disasters.

If a water well has been impacted by flooding, take the necessary steps, and contact a water well professional to ensure that testing and the disinfection of the well is handled safely.  You may also consider a call to your local Environmental Health office for additional advice.

A water well is a fundamental asset, be sure to protect it as best possible prior to a water well flooding. When possible, a water well should never be constructed in an area that has the potential to flood, it’s best to locate water wells on higher-ground.

Water Testing FAQ

1) Please read water sampling instructions completely before proceeding with filling the sample bottles provided in the water test kit.

2) Complete each bottle label and the water testing chain-of custody form completely. The water testing laboratory reserves the right to refuse water samples with incomplete chain-of custody forms. Contact laboratory personnel with any questions regarding the chain-of custody forms.

For Regulated Facilities, when sampling water from a Chlorinated Distribution System please include your Residual Chlorine (Free & Total Chlorine) results in the area provided on the chain-of custody form.

3) Choose a water sampling location that accurately represents the quality of the water being sampled such as a kitchen faucet. For registered water system samples, sample at the registered locations. When sampling distribution/plumbing system taps, it’s not advisable to sample from an unprotected outside hose-bib or garden hose.

It is recommend that sample be taken from a point-of-consumption such as the kitchen sink faucet or bathroom sink faucet. Do not sample your water from a non-consumption point unless absolutely necessary without any other option.

4) Always remove any aerators, hose attachments, filters and strainers from faucets as they can be a point of contamination. Also remove the screen at the end of the tap, when possible.

5) Sterilize the open end of the water faucet with an alcohol swab; disinfecting wipes e.g. Chlorox; or bleach.  If you disinfect with a match or flame, ensure that there are no plastic or rubber parts on the end of the tap.  Once you have sterilized the end of the tap, do not touch it with your fingers or wipe it with un-sterilized cloths such as a dishcloth.  It’s easy to recontaminate the faucet possibly causing your water sample to be contaminated.

6) Turn on the COLD water side of the faucet and flush the waterline long enough to ensure fresh water is in the line, we suggest this will generally require 5 to 10 minutes of running the water.

7) DO NOT PRE-RINSE THE BOTTLE. Carefully remove the cap from the water sample bottle without touching the mouth of the bottle.  Carefully hold the sample bottle near the base of the bottle and fill to the shoulder (water fill line) leaving approximately one inch of head-space.

It’s important to not touch the inside of the cap or the lip of the bottle – the inside of the cap should not come in contact with anything other than the atmosphere and the sample. Also try to avoid any back splash from sink. Tightly replace the cap on your water sample bottle. 

8) Keep the sample cold (between 2 and 10 degree C – never freeze a water sample). If samples are being stored in a refrigerator prior to shipping the samples to the local water testing laboratory then it’s always a good idea to place the water samples in a clean plastic zip-lock bag to keep the samples safe and clean,  once the sample a ready for shipping they should be placed in the small coller that is provided with pre-frozen ice-pack to maintain temperature during transit.

9) Transport samples to the lab in a rigid walled sealed box or cooler. Transport to the lab within 24 hours
(ideally the same day). Samples expire 48 hours after sample collection time

A: If your drinking water comes from a private well in the Fraser Valley, water testing should be done by a certified water testing lab near you to see your drinking water us safe for you and your family to drink and prepare food. Drinking unsafe drinking water can make people sick. Even if you’re not currently sick, your well water may be unsafe.  Some contaminants found in well water can cause long-term health issues.

A: All purveyors of certified water systems in the Fraser Valley and throughout British Columbia are required to test the water regularly.

This includes including small private systems, such as shared wells, restaurants or trailer parks, cooperatively owned systems, such as strata properties, and larger municipal systems owned by local governments.

A: If you own a private well in the Fraser Valley, it’s important to have your well water tested to determine if your water is safe to drink. Just because your neighbor’s water well has been tested and found to be safe this is not an indication that your water is also safe, all Fraser Valley water wells should be tested at least once a year and some more often.

Remember, the safety of your well water depends on surface and underground geology, the depth and construction of the well. Even deep drilled wells can be susceptible to contamination if surface water enters the well from the top of the well or from surface fractures in the rock or a leaking and even damaged casing.

It’s important to note that a water test report will only tell you about the quality of your water on the day that you draw the sample. Well water quality can also be seasonal. Heavy rain, melting snow, drought, floods or other events such as seasonal land-use may cause contamination. Water wells need to be tested on a regular basis, maintain a file for the water test reports for future reference.

A: What is the difference between the Canadian Drinking Water Guidelines and Canadian Drinking Water Standards?

Canadian Drinking Water Standard – a mandatory limit that must not be exceeded; drinking water standards often indicate a legal duty or obligation.

Canadian Drinking Water Guideline – a recommended limit that should not be exceeded; guidelines are not intended to be standards of practice, or indicate a legal duty or obligation, but in certain circumstances they could assist in evaluation and improvement.

A: There can be many harmful substances that you cannot taste, see or smell, such as bacteria and chemicals that could affect your health.

Contaminates can enter a well water both from the surface and ground and can be from natural sources or human activities.

For example, nearby farming and agricultural activities or septic systems, if built or maintained improperly, could lead to increased nitrates and fertilizers seeping into soil and contaminating your well water, even deep drilled wells.

The lack of good water well maintenance may also cause contamination of your Fraser Valley Well Water.

A: There are 2 categories of water tests for well water:

1. Bacteriological Water Testing
2. Chemical Water Testing

Bacteriological Water Testing

Bacteriological testing should be done 2 or 3 times a year. Two common types of bacteria found in water are: Total Coliform and E.coli.

Total Coliform

Total Coliform include bacteria found in soil, surface water, and the intestinal tracts of animals. Finding total coliforms in a well may not mean that the water is unsafe to drink, but does indicate:

1) The well may require improved sanitation or physical upgrades.
2) The well may be subject to surface contamination.

Escherichia coli (E. coli)

E. coli originates in the intestinal tracts of animals. The presence of E. coli in your well water may mean fecal matter has entered the well. Fecal organisms cause stomach and intestinal illnesses, including diarrhea and nausea, and may even lead to death. Babies, children, elderly or people with immune deficiencies or other illnesses may be affected more severely.
E. coli in your drinking water is an immediate health concern and the water is not safe to drink.
For more information, see the British Columbia Ministry of Environment’s fact sheet on Total, Fecal & E. coli Bacteria in Groundwater 

Chemical Testing

Testing water for chemicals should be done on a routine basis, typically at a minimum of every 5 years. Chemicals commonly of concern in the Fraser Valley’s groundwater resources are: nitrates, fluoride and metals such as arsenic, lead, copper and manganese.


High levels of nitrates have been found in numerous wells throughout the Fraser Valley. This usually occurs in areas where groundwater may be contaminated by surface activities such as agriculture or farming, drilled wells can be susceptible but shallow wells are especially vulnerable to nitrate contamination.


Since well water comes from the underground, different metals in the soil and rock can leach or dissolved into the water. Some metals, such as arsenic can have serious and long-term health effects if they are found in high amounts.

A: Local Water Well Pros drillers are educated and certified under the BC well drillers apprenticeship program must abide by or exceed the water well drilling regulations for British Columbia.

A: Arsenic is known to cause cancer, as well as many other serious health problems. Arsenic levels tend to be higher in drinking water that comes from groundwater sources, such as water wells, as opposed to water from surface sources, such as lakes or reservoirs.

Arsenic is a natural element that can be found in rocks and soil, water, air, and in plants and animals. It can also be released into the environment from some agricultural and industrial sources.

Other metals such as lead, and copper can also leach out of pipes and soldered joints. Water of low PH will typically be much more aggressive. For some, but not all metals, you may notice taste, odor, or staining of fixtures.

Local Water Well Pros

 Abbotsford, Chilliwack, Yarrow, Sardis, Clearbrook, Harrison Lake, Hope, Langley, Fort Langley, Surrey, Vancouver,
Aldergrove, Cloverdale, Pitt Meadows, Maple Ridge, Albion, Whonnock, Ruskin, Mission, Dewdney

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