Basement water / seepage

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Related info

Flood resilience and recovery

Sanitary sewer backup

Developing your basement


Slope stability


Ground water seeping into basements is a common problem, but can cause significant water damage to property and can be costly for homeowners. This page provides background information, solutions and preventative measures for typical basement water problems.

Leave the house immediately if:

  You smell natural gas, or
  Water has reached electrical outlets, or
  Your neighbourhood is under an evacuation notice.

If your basement is flooded, proceed with caution! Do not enter a flooded basement until the fire department, utility service or licensed electrician has determined that it is safe.


Who should I call?

  Fire or Medical Emergency: 911
  City Gas Emergency (24 hours) 403.529.8191
  City Electric Emergency (24 hours) 403.529.8260

Emergency and service workers will determine whether or not the basement is safe to enter. However, basement flooding is the responsibility of the homeowner. The City of Medicine Hat does not remove water or clean up flooded basements.



Sanitary sewer backup:

If the cause of the flooding is a plugged sanitary sewer main (between house and street), you may contact:

  A private plumbing or drain cleaning service (check local listings), or

  City Environmental Utilities Dept. (24 hours) 403.502.8042
Environmental Utilities offers a courtesy service where workers will clear the blockage. This service is available for properties within city limits, between 8:00 am and 4:00 pm, seven days a week.

  For more information, visit Sanitary Sewer Services


Water in basement? Here's steps you can take:

Call your insurance company. It is up to the homeowner (policy holder) whether or not to contact their home insurance provider. If the flooding is significant, this is highly recommended. Your insurance company will arrange for proper restoration and will process your insurance claim.

Do not enter a flooded basement until it is safe. Emergency and service workers will determine when it is safe to enter.

Once its safe, take clear photos of damaged areas and items for insurance claim purposes before you remove anything.

Once its safe, salvage important belongings as soon as possible to minimize damage.

If you are doing clean-up yourself, be aware of health risks and proper sanitation methods. Refer to the Cleaning up after a flood section at the link below:

  Flood resilience and recovery

Preventing basement seepage

Why does it happen? Basement seepage (also called infiltration flooding) occurs when water is absorbed by the soil and raises the level of the underground water table. Water seeps through the soil and eventually reaches the building foundations. Concrete is porous, and the water will also work its way into basements through cracks in the foundation walls or floor slab, through joints in the foundation, or through clogged window wells.
What you can do. Below are methods homeowners can use to prevent or reduce basement seepage:


Always have properly-installed eavestroughs (rain gutters) and downspouts on your house. Catching water from the roof and and directing it away from the walls of the house are critical factors in keeping the basement dry.

Keep them flowing

The job of eavestroughs, downspouts and downspout extensions is to divert water away from your foundation. If they become clogged with leaves, dirt or other debris, they cannot do their job, so keep them clean.

Ensure that eavestroughs have enough slope to allow for optimum water movement towards the downspouts. Sometimes a sagging eavestrough can be repositioned to prevent pooling and reestablish the slope. If it cannot be repositioned, replace it.


Plug the leaks

A ladder, silicone and time are often all you need to seal joints or cracks in eavestroughs, downspouts and downspout extensions. Clean them first, and apply outdoor-grade silicone on the inside of eavestroughs. If there are areas that are heavily damaged, you can purchase replacement parts or contact a qualified professional to do the repairs.


The right direction

Ideally, the downspout should end in an elbow and extension that directs the water 1.5 to 2 meters (5 to 6 feet) away from your foundation and towards the street or back lane. However, make sure that it does not extend to your neighbour's property, nor divert the water onto their property. The extension should be at a 30 degree or more angle in relation to the ground. Leave the extension down all of the time or put it down whenever rain or snowmelt is expected.

Splash pads may be used to direct the water that is discharged from the downspout extension, and they also reduce the chance of the water eroding a hole into the ground.

Rain barrels can help minimize residential flooding during heavy rains and provide water for gardening. Learn how to make an inexpensive rain barrel from a garbage can:
icon_PDFHow to make a rain barrel

lot-drainage figures

Rain rain, flow away

Proper lot grading is one of the most important factors in preventing water from getting into a home. For decades, the City of Medicine Hat has required that new neighbourhoods be graded according to an approved subdivision lot grading plan. Site-specific grade control plans are also required before building a new house on a lot. But regardless of the age of the house, the grading of lots in mature neighbourhoods can be vastly improved with some relatively simple measures.

  icon_PDFLot drainage diagram

Remember, we are here to help!
If you are unsure about the drainage pattern for your lot, you may contact a member of the Engineering team at Planning and Development Services. As a courtesy service, they can provide you with drainage pattern information for your area, and may be able to offer advice for your particular drainage concern. It may be helpful if you have photos of your lot or situation.

Ask to speak to an Engineering staff member at:
Planning & Development Services
2nd floor, Medicine Hat City Hall
580 1st Street SE
Phone 403.529.8374

grading-poor vs good

Graded landscaping

To ensure that surface water flows away from your foundation, make sure that there is a minimum slope of the ground from the outside wall. A minimum drop of 10-15 centimeters for the first 1.5 meters from the wall is recommended. Add clay soil to achieve the recommended grade, compact it, then add sod or groundcover as desired.

Don't forget to backfill underneath stairs, steps and decks as well, using the same slope. Ground settles over time, so check the grade yearly and add soil where necessary.

  icon_PDFGrading diagram

•  Video: Simple way to ensure proper grading around your home (YouTube)



A swale is a depression created in the ground that carries runoff by gravity away from your home and property. The swale collects the water by being at the lowest point in a given area and then it is sloped to the direction where the water is to flow. On residential lots, this means to the street, a back lane, or sometimes to a common rear swale in a green strip. Not nearly as deep as a ditch, a swale will typically be landscaped with turf or rocks, and will be dry most of the time. In areas of heavier water flow, a concrete swale may be installed which accomplishes the same thing.

New neighbourhoods in Medicine Hat must have approved grading plans before being developed, to allow for proper drainage. Site-specific grade control plans are also required before building a new house on a lot.  These plans are engineered so that water from one lot will not flow onto neighbouring lots, but instead to the front and/or back of the lot and away from homes. To help channel the water, swales are often a part of the design.

If you have a swale on your property, do not block or restrict it in any way. For instance, do not fill it with soil, install a shed over it, plant a vegetable garden on it, or excavate a concrete swale, as this will restrict the flow of runoff. That could cause ponding in your yard and/or your neighbour's yard, leading to basement seepage and other drainage problems.

Regularly trim and rake grass in natural swales and control weed growth. Swales that are filled with long grass, weeds or lawn clippings can become less effective at draining runoff during heavy rainstorms. Swales created during an area's development stage are usually near property lines.

gravel_swaleExample of landscaped swale

If you would like to build an internal swale on your property to help with drainage, you should:

  Talk to an Engineering staff member at Planning & Development Services for input and advice (contact information above).

  Consider seeking qualified help from landscaping professionals if you are unfamiliar with this type of work.

•  Obtain a Development Permit, which is required for changing the drainage pattern of a lot. To apply, visit Development Permits. 



Window wells

If there are basement windows at or near ground level, you may want to install a window well. This not only allows for properly grading of the landscaping, but prevents soil from rotting the window sills.

Typically made of galvanized steel, the window well must be installed to ensure proper drainage to the footings. The area around the foundation and window should be excavated down to the footing and backfilled with clean, course gravel to within 6 inches of the window sill. It is recommended that a coating of dampproofing material be applied to the exterior of the foundation wall to prevent ingress of surface water.

If the window well serves a bedroom window, additional requirements are needed to ensure egress is provided in an emergency. The window well must provide an unobstructed opening of at least 76 cm (30”) from the foundation wall. If the egress window swings into the window well, further clearance is needed.

Some existing window wells may not drain properly and further techniques may be necessary. If you are not experienced with installing or repairing window wells, seek the advice of a qualified professional.

For specific questions about window wells, contact a Safety Codes Officer in Planning and Development Services.


DIY crack filling

Filling and sealing cracks in a home's foundation is helpful in preventing basement seepage. Visible external cracks can easily be filled with waterproof caulking or foundation tar. Also look for cracks or spaces on driveways, sidewalks and patios that are next to the foundation wall.

For obvious reasons, locating a problematic crack in a foundation can be difficult. If seepage is in a specific area of a basement, then digging with shovels along the foundation wall may be possible to some extent. Cracks that are discovered may be sealed with foundation tar and thick plastic sheeting. Soil should be well compacted as it is replaced. For this type of repair, the best option for some homeowners may be to seek the help of a qualified professional.

waterproofing_existing_house Excavation and waterproofing for an existing house

Professional foundation sealing

If basement seepage is severe and other solutions are not working, it is likely that more extensive (and costly) measures are necessary to remedy the situation. The course of action and cost will vary depending on the home and situation. In extreme cases, it will be necessary to excavate the soil around the entire foundation, install waterproofing membrane on the exterior foundation walls, install weeping tile at the bottom of the foundation and then backfill. The weeping tile will drain to a sump pit where a sump pump (typically) will discharge drainage water safely.

Hiring a professional company that specializes in waterproofing basements is crucial. Such a company will be experienced with various solutions, will have the needed heavy equipment,  and will be familiar with obtaining necessary permits. The City of Medicine Hat does not recommend nor endorse private contractors. Search local listings and check references.

All homes built in Medicine Hat after 1984 are required to have weeping tile installed for foundation drainage. For homes in flood-prone areas, weeping tile, sump pumps and backwater valves are highly recommended.

•  If you have questions about these methods, contact a City Safety Codes Officer at 403.529.8374.

  See map of    icon_PDFFlood Hazard Areas in Medicine Hat


Weeping tile

Weeping tile is a perforated plastic pipe that is installed at the bottom of a building's foundation, around the outside, typically during construction. It is laid upon a bed of gravel, allowing excess groundwater to seep into it. The accumulated water will then drain by gravity (or pumped by a sump pump) to the city's storm sewer system. In some cases where this is not feasible, The City of Medicine Hat will allow weeping tile to connect to the sanitary sewer system instead. All homes built after 1984 in Medicine Hat are required to have weeping tile installed.

If necessary, weeping tile can be effectively retrofitted to older homes in some cases, although it is expensive. The soil around the foundation must be excavated so the weeping tile can be installed against the footings. Some professional companies that specialize in waterproofing have devised methods to install weeping tile from inside the basement. 

Old weeping tile can become damaged. It can deteriorate, break and fail over time, particularly the very old clay variety. This, too, can result in basement seepage. A professional can run a tiny inspection camera into the line to determine its condition, and can offer solution options.

Hiring a qualified contractor is critical for installing any exterior or interior weeping tile system. The City of Medicine Hat does not recommend nor endorse private contractors. Search local listings and check references.

sump-photoExample of sump pit with pump

Sump pits

A sump pit (or sump container) it is part of a home's foundation drainage system and is typically situated under the basement floor. Water drains from the weeping tile surrounding the foundation and is collected in the sump pit. Installing a sump pump is one method of draining the pit when it cannot be drained by gravity. The pump activates when water reaches a certain level in the pit.

All new homes with basements built in Medicine Hat after June 1, 2011 are required to have a sump pit. A sump pump is not a regulatory requirement in Medicine Hat, but it may be a technical requirement to remove accumulated water, depending on the soil conditions of the area.

Where does the drainage water get diverted to?

  City's storm sewer system (by underground connection); or
  City's sanitary sewer system (if necessary, must have City approval); or
  Above ground on owner's lot (min. 2m from foundation, must not affect neighbours); or
  A dry well on owner's lot (min. 5m from foundation).

  Video: How to Install a Dry Well for a Sump Pump (YouTube)


Sump pumps do not last forever. Depending on the type and the water conditions, they may last from 5 to 25 years. If your pump has stopped working, get it replaced right away. Follow manufacturer's recommendations, and learn how to maintain your sump pump.  You may also choose to have a professional plumber or basement waterproofing specialist make an annual service call to check and service your system.

  icon_PDFSump pump diagram

  For construction guidelines, see: Sump Design Criteria Bulletin (Nov 2011)

  For sump container & discharge requirements, see: Safety Codes Newsletter (May 2011)


Backwater valves

Backwater sanitary valves are not directly related to basement seepage, but are designed to prevent sanitary sewer backup in basements. Typically installed in the main wastewater line, its job is to prevent sewage from returning up the line and entering the basement through floor drains, toilets, sinks and tubs.

Backwater sanitary valves are recommended for homes and businesses which are prone to flooding and sewer backup. Installation must be done by a licensed plumbing professional, and a plumbing permit is required. In most cases, you can check to see if the backwater valve is working properly by looking though the clear cover on the access box. Follow manufacturer's recommendations for cleaning and maintenance.

backwater_valve_exampleExample of sanitary backwater valve, installed.

  Video: Backwater valves (YouTube)

  For more info about overland flooding in Medicine Hat, visit Flood resilience and recovery

Why does backup occur in sanitary sewers? This can happen if the system becomes overwhelmed due to major flood event, for instance. Blockages in the sewer line can prevent proper drainage, also causing sewage to backup. Additionally, in some older homes, the eavestroughs may be connected to the sanitary line, a practice no longer allowed. This can also overload the sanitary sewer line during heavy rainstorms. 

  For more information about sanitary sewer backup visit  Environmental Utilities

Regular maintenance of your home drainage system can often be the difference between staying dry or having a wet basement. Check conditions in and around your home once a year, and fix problems as soon as possible. If you are unsure how to deal with a potential problem, contact a professional.


Outside: Annual Check

Foundation and Grading

  Check the slope of the ground from basement walls.
  Look for soil settling, especially under stairs & decks.
  Add clay soil to any low spots.
  Make sure window wells are not retaining water; clean out debris.
  Fill and seal any visible cracks in foundation.
  Look for cracks or gaps on concrete slabs next to foundation wall (driveway, sidewalk, patio) and caulk/waterproof where required.

Eavestroughs and Downspouts

  Clean out leaves, dirt and debris.
  Tighten elbows and other connections.
  Caulk and seal any leaks.
  Replace sagging or badly damaged sections.

Splash Pads and Extensions

  Reconnect any loose splash pads or extensions.
  Replace damaged extensions.
  Roll out extensions to make sure they work and check for leaks.


Inside: Annual Check

Basement walls and floor

  Check for moisture or water stains on walls and floor.
  Look for rot or mold at the bottoms of walls or baseboards.
  Check for peeling or bubbling paint on walls.
  Fill and seal any visible cracks in exposed foundation walls.

Sump Pump

  Ensure that the pump has power.
  Test the pump and discharge by pouring a bucket of water into the sump pit.
  Check the discharge pipe and repair any leaks.
  If your sump pump pipe discharges outside, keep it disconnected during winter months to avoid freezing.

Backwater valve

  Open the top and clean out any debris.
  Check the flapper; make sure it is moving freely.


General Best Practices

Be insured; Be ready
Make certain that your homeowner's or tenant's insurance policy is adequate for your needs; check the coverage for damages that are caused by infiltration and overland flooding. Do not allow your policy to lapse due to non-payment. Have your insurance company's emergency number handy; entering it in your mobile phone is a smart idea.

Keep valuables out of basement
It is not recommended that important papers, heirlooms or valuable equipment be kept in a basement, just in case of flooding. If unavoidable, consider using waterproof containers.

Reduce lawn watering
Prolonged lawn watering not only affects your utility bill, it greatly increases the water table levels in the soil. Minimize watering to help avoid basement seepage. Turn off automated sprinkler systems during rainy periods.

  To learn more, visit Outdoor water conservation

Fats, oils & grease - Store it, don't pour it
Do not pour fats, oils and grease ("FOG") down drains. It clings to the insides of sewer pipes and can cause blockages. To dispose of FOG, pour it into a disposable can or jar until cool. Wipe pans and dishes with paper towels. Then dispose of these items in your household trash.

  To learn more, see   icon_PDFFats, Oils & Grease (FOG)

Be careful what you flush
Help prevent sewer backups by not flushing "unflushables" down a toilet. Things like diapers, cotton swabs, feminine hygiene products, trash, etc. do not disintegrate, and may stick together and form a blockage. So-called "flushable" wipes are becoming the leading cause of city sewer line blockages!

  To learn more, see   icon_PDFUnflushables


Helpful references

The document below is made available by the Institute for Catastrophic Loss Reduction, and discusses solutions for all types of basement flooding.

  icon_PDFHandbook for Reducing Basement Flooding

City of Medicine Hat brochure with general information about basement seepage:

  icon_PDFBasement Water Problems