Basement flooding is a widespread problem and causes millions of dollars in damage to personal property, not to mention huge personal efforts in rehabilitation to fix the damage caused, and to replace items lost. Clearly, it is in a home owner’s best interest never to experience a basement flood at all.

Whether you have flooded or not, part of this discussion will be based on principles of home plumbing and drainage reviewed.

Here are a list of measures a home owner can take to protect their basement from flooding, the majority of which has been adopted from the Handbook for Reducing Basement Flooding.

If your home has a basement, you can have a basement flood. All measures listed will provide the knowledge and best practices on how to avoid a flood. However, the risk of basement flooding is never entirely avoidable. If you have a basement, there will always be a risk that conditions can occur that will cause a basement flood.

Flood Reduction Options for Homeowners

Knowledge and Understanding
  • Talk to your municipality or local utility about basement flooding
  • Notify your municipality if and when you have experienced basement flooding
  • Undertake a detailed plumbing investigation on your home
  • Understand your insurance coverage
  • Know your responsibilities as a homeowner
Lifestyle and Use of Space
  • Avoid pouring fats, oils and grease down your sinks
  • Reduce household water use during heavy rainfall
  • Avoid storing anything directly on the basement floor
  • Avoid making the basement high-value living space
Simple and Inexpensive
  • Keep the nearest catch basins clear of debris
  • Proactively seal cracks and holes in your foundation walls and floor
  • Look for and eliminate any direct surface inflow points
  • Maintain your eaves troughs and downspouts
  • Downspout disconnection, extension and splash pads
Highly Effective, with more Effort and Expense
  • Control surface water around your home: lot grading, backfilling and swales
  • Control ground water around your foundation: weeping tiles, sump-pits and sump pumps
  • Install a backwater sanitary valve
  • Conduct sewer lateral maintenance
  • Sever the storm lateral
  • Consider the implications of reverse-slope driveways
  • Consider window wells and window-well covers

Knowledge and Understanding

Part of reducing the risk of basement flooding for your home is having knowledge and a solid understanding of such things as the general flood risk of your area, what the municipality knows or does not know about it, insurance considerations, as well as basic knowledge about how your home’s plumbing and drainage systems work. The following section discusses five things you can do to improve your knowledge of flood risks and implications.

1. Talk to your Municipality about Basement Flooding

Stormwater, storm sewers and general surface drainage issues are managed by City Engineering.
Sanitary sewers and treatment are managed by Utilities Kingston.

Whether your home has experienced basement flooding or not, one place to get started is your local municipality.

Some questions to ask municipal staff:

  • What type of servicing do I have to my home?
  • What is your municipality doing to address flooding in the community?
  • What can I do as a homeowner to protect myself and protect my neighbours?
  • Where can I find more information on basement flooding?
  • Does the municipality offer any financial assistance programs?

2. Notify your Municipality of Flooding Incidents

Basement flooding can occur at random locations, or it can occur in concentrated areas. Regardless, it is important to let the municipality know that your home has flooded, because it can help direct efforts to understand why flooding occurred there and may assist in identifying solutions for flood risk reduction in your area. The more reports that are filed from a given area, the more resources are likely to be committed to understanding the problem.

3. Undertake a Plumbing Investigation on your Home

Part of reducing the risk of basement floods is to understand how your drainage and plumbing work. Every home is different, and homes over time have been built with ever changing building practice and building codes. Things that are valuable to know about your home’s plumbing include:

  • Where is your sanitary sewer lateral located? Do I have trees on top of it?
  • Does your home also have a storm sewer lateral? If so, where does it go?
  • Do you have a backwater sanitary valve on your lateral? Do you know how to maintain it?
  • How does your foundation drainage work? Is it connected in to the sanitary sewer?
  • Does the municipality offer any financial assistance programs?
  • Do you have a sump and sump pumps? If yes, where do they discharge?
  • Where do your downspouts go? Are they going into the sanitary sewer?
To understand these elements of your home’s plumbing, you may wish to engage a licensed plumber who can conduct specialized testing or inspection, perhaps through using a video camera.

Sometimes it is difficult to figure out how the foundation drainage works and where it drains to, and a video inspection may not be enough. Some of this learning may require some extra efforts from specialized contractors, such as camera inspections or dye-testing. The City and Utilities Kingston may have some of this information which is why it is worthwhile speaking to your municipality first.

4. Understand your Insurance Coverage

Until recently in Canada, insurance did not cover any flood damages related to “overland flooding”, including flooding that is caused by heavy rainfall, riverine flooding and all other sources of overland flooding. This also includes flooding occurring due to cracks in the foundation, or up through the sump, should any sump pumps fail to operate properly. Water Protection Insurance Coverage does exist now that covers overland water damage – be sure you have that water insurance coverage.

Speak directly to your insurance broker to be 100% certain about the specifics of your own policy when it comes to sewage backups and water damage in general

Typical home insurance, on the other hand, does offer coverage for sewer backup, whether from the storm or sanitary sewer system.

Water protection coverage is not necessarily automatic. It is prudent to verify with your insurer that you are insured for sewage backups, and to review the stipulations of that coverage. For example, what would happen to your coverage if you were to make a claim? How does it affect your rates, or insurability? Learn about this aspect of your coverage to understand the implications and know what is covered and what is not. If your home is not insurable due to previous flooding claims, find out what you can do to reinstate coverage, if anything. Check to see if you qualify for a financial assistance program.

5. Know your Responsibilities as a Homeowner

As a homeowner, you are responsible for your connections to the municipal systems, and for what you put into those connections. There are a few items that are noteworthy for the average home owner to know and understand:

  • The sewer lateral has shared ownership. The municipality is responsible for the portion from the property line to the sewer main. The homeowner is responsible for the portion on private-property, generally from the property line to the home. Responsibility includes general maintenance and upkeep of this connecting pipe.
  • Sanitary sewage is the only thing that is permitted to be discharged to the sewer, and this means that connections from roof leaders, sump pumps and weeping tiles are all considered illegal connections (Clause 3.11). Not only do these connections increase your own risk of flooding, they also increase the risk of your neighbours flooding, and increase the occurrence of sewage bypasses to the environment.

Lifestyle and Use of Space

There are a number of simple things a homeowner can do to reduce their risk of basement flooding.

6. Avoid Pouring Fats, Oils, and Grease Down the Drain

Fats, oils and grease can cause a sewage backup because they have a tendency to solidify and accumulate in your internal plumbing, the sanitary lateral or the sewer main. While fat, oil and grease may be liquid when warm, they quickly cool and solidify as they flow through the plumbing pipe network. Flushing down with hot-water generally does not eliminate this risk, it may just get the substance a bit further down into the plumbing system.

The municipality will not take responsibility for any blockage due to fat, oil or grease accumulation and blockage that is found on any portion of the lateral.

7. Reduce Household Water-Use during Heavy Rains

While a rainy day may seem like a great time to get some domestic chores done, including doing laundry or running the dishwasher, it does increase flood risk for yourself and possibly your neighbours. To reduce the risk and reduce the load on the sewer system, wait until a few hours after heavy rains to undertake heavy water-use practices in the home. This helps you and your neighbours!

This is particularly important if you have a backwater sanitary valve on your sanitary sewer. If the backwater sanitary valve is closed because the sewer is full, you risk flooding your home since your own domestic wastewater will not be able to drain to the sewer main.

8. Avoid Storage on your Basement Floor

The lowest level of your home is your basement floor, and it is at the greatest risk of getting flooded. The basement floor is where water will accumulate first, and anything stored on the floor is at the greatest risk. If you do need to store items on the floor, consider lifting them up a bit on shelving or supports, or using water-tight containers.

9. Avoid making the Basement High-Value Living Space

A big change in home use over the past 50 years has been the increased reliance on basement space as useable living space. Not only does this mean that basements are finished, but they may also be used as rooms for high-value items, such as recreation rooms or computing/gaming rooms, often equipped with expensive electronics and exercise equipment. In the insurance industry, this is considered to be the primary cause of a significant and consistent increasing trend in the average basement flood-related claim value, which is in the order of $15,000 to $20,000 per claim (2004/2005 figures), although $50,000-$100,000 is not unheard of.

This trend indicates that homeowners are either unaware of the risk, or understand the risk and choose to take the risk to utilize the space. As mentioned above, all basements are at risk of flooding. Even making use of all the recommendations herein does not eliminate the risk, it just reduces it. A good example is sewer lateral maintenance. All shingle roofs will eventually leak, all driveways will crack, and eventually, all sewer laterals will fail, and unfortunately, failure of a sewer lateral is usually only detected when wastewater is coming up out of the floor drain. When planning how to use your basement space, this should be taken into consideration.

Simple and Inexpensive

The following lists some relatively simple and inexpensive measures a homeowner can do themselves to reduce flood risk. If they sound complicated or challenging, you may wish to consider hiring a qualified contractor.

10. Keep the Nearest Catch Basins Clear of Debris

Catch basins are the storm sewer grates located on the street, and they are responsible for storm runoff drainage to the storm sewer. In some cases, you might even have one in your front or back yard. Often, particularly in the spring after snowmelt or in the fall when the leaves drop off the trees, catch basin grates can get blocked by debris that accumulates on top of them. This may cause or worsen localized street flooding, which may increase the risk of high groundwater levels and possibly surface flooding of neighbouring areas including homes, all occurrences that are not covered by insurance. If you know of a catch basin outside your house on the road or even on your lawn, or neighbour’s lawn, consider taking ownership of it and keeping it clear of debris. This simple activity might save you or your neighbour from flood problems.

Catch basin maintenance is the responsibility of the City of Kingston Public Works Department, however, in certain times of the year, it is difficult for Public Works to maintain all catch basins at the same time. So, if you see one near you, and are willing and able, do yourself and your neighbours a favour and kick the leaves off of it. If not, call the Customer Service Representatives at (613) 546-0000.

11. Seal the Cracks in your Foundation Walls and Floor

As mentioned earlier, while some insurers may offer it as an extra provision to your home insurance policy, in most cases, home insurance does not cover floods occurring from surface-water or ground-water getting into your basement, whether by direct overland routes of via cracks or holes in your foundation walls or floor.

As with anything, foundations deteriorate over time. With this deterioration, and potential construction flaws and differential settling, cracks may form in your foundation, either on the walls or on the floor. When the groundwater level around your home is high, it may submerge these cracks and pressurize them to the point where they leak water. Leakage rates may be minimal, but they can also be substantial, depending in how much water there is near the crack, and how big the crack is. So, just like you get the shingles on your roof replaced, say every 10-15 years, it is also important to maintain your foundation.

In many cases, you may be able to simply seal the cracks from inside the basement, without any need to dig. But for larger cracks, or particularly persistent ones, contracting the help of professionals may be required as these may be candidates for more substantial repairs done on the exterior of the house. You may wish to flip through the City’s Yellow Pages for “Foundation Repair” to help find a suitable contractor.

12. Eliminate any Overland Flow Routes

Entry of water from overland flow paths are another form of flooding not covered by insurance. There are many potential overland flow paths, but generally this is referring to any path that allows surface water to get in. Such routes may include service holes into the basement, such as holes intentionally constructed for incoming electrical mains, or natural gas for powering a furnace for example. Routes also include gaps beneath doors, or leakage around aging window frames or window wells, among others.

Home owners should take the necessary steps to ensure that all potential overland flow routes are properly sealed, and even better, also ensure that the source of the water at those points be diverted elsewhere by proper site grading.

Note that reverse slope driveways and window wells are both forms of overland flow routes that are discussed in further detail later on.

13. Maintain your Eavestroughs and Downspouts

One good way to ensure effective drainage of your roof is to maintain your eavestroughs and downspouts. Ensure they are clear of debris and not partially or fully plugged. Plugged eaves and downspouts may result in water filling up and spilling over and discharging to locations close to the foundation. In addition, blockages allow for water to freeze and expand and break apart the seam on downspouts, such that water may spill out down the wall.

A big rainfall is a great time to take a walk around your home, and make sure everything is working as it should.

14. Disconnection of Downspouts

While standard practice in the 1960’s and earlier, municipalities across the world have recognized that downspouts discharging to a sanitary system serve as significant contributors to sewer surcharging, bypasses and basement flooding. This is because during major rain storms, rooftops generate a considerable amount of run-off, not only in terms of volume, but also in terms of flow rate, since the runoff occurs very quickly off slanted roofs.

f your downspouts are entering a pipe that goes below grade, in all likelihood, you have illegal connections and should take the necessary steps to disconnect them.

Best practice for downspouts, where feasible, is to discharge downspouts via extensions to a splash pad, and ultimately out to a grassy or otherwise permeable surface where the water can infiltrate naturally. Consider adding a rain barrel to store some of that clean water for watering your lawn or garden!

Ideally, where possible, downspouts should discharge as far away from the foundation as possible, or at least a minimum of two metres to a pervious surface such as a lawn or garden. A couple of things to consider:)

  • Be sure that the discharge location keeps the water on your property, as it is illegal to create additional flood risk for a neighbour.
  • In some circumstances, it is simply not possible to discharge all your downspouts to your own lawn or garden. Avoid discharging to a sidewalk or walkway. This could create a slip hazard. In some circumstances, exemptions may be available.
  • In many cases, adding a two meter extension to the bottom of a downspout creates a trip hazard or an impediment for walking by your home. In these situations, consider a swivelling or folding downspout extension that would allow you to fold it up and away while say, cutting the lawn or hosting a social event.