The short answer
Sewer backup insurance is usually an endorsement added to a home, condo or tenant policy. It pays for damage when sewage or storm water is forced back into the home through floor drains, toilets, sinks or a sump. It normally carries its own limit, and sometimes its own deductible, separate from the rest of the policy. A backwater valve, a working sump and an honest description of the basement shape what a licensed broker can find.
- Owners of a finished basement with a floor drain, laundry or bathroom below grade
- Households in older neighbourhoods where storm water and wastewater may share one pipe
- Anyone who has had sewage come up through a drain, or whose neighbours have
- Owners comparing the backup limit on a renewal against what the basement now holds
- Buyers who want to know whether a backwater valve is already installed
4 licensed brokers in the network handle this. In Alberta, Canada, a request for sewer backup insurance can be offered to up to three of them, chosen because they are licensed for this line and place. They are test brokers while we are in demo.
See the brokers → Outside Alberta, Canada you can prepare and save a request today; sending opens place by place. Brokers answer with their own quotes. Broker.insure does not quote, advise or take commission.
01 / What it covers
The parts worth understanding
The endorsement itself
Most home policies leave out water that backs up through drains unless an endorsement is added. Some insurers bundle it into a broader water package; others sell it on its own. Check the declarations page for the exact wording, not just a line that mentions water.
A limit of its own
The backup endorsement usually caps what it pays at an amount well below the building limit. A finished basement with flooring, drywall, a bathroom and stored belongings can pass a modest cap quickly, so compare the limit with what is actually down there.
Cleanup and restoration
Sewage is a contamination problem as well as a water problem. Extraction, disinfection, removing wet drywall and insulation, and drying equipment often make up much of a backup claim before any rebuilding starts.
Belongings in the basement
Furniture, electronics, a chest freezer and boxes stored on the floor are typically claimed as contents, but they still sit within the backup limit. Shelving that keeps items off the floor reduces what is exposed.
Sump overflow and pump failure
Water rising out of a sump pit when a pump fails or the power goes out is read differently by different wordings. Some include it under backup and some exclude a failed pump, so ask how each insurer treats it.
The pipe under the yard
Repairing a cracked or root-blocked sewer line between the house and the street is usually not part of the backup endorsement. Some insurers offer a separate service line option for underground pipes; ask whether one is available.
What it does not reach
Backup cover does not pay for water flowing in across the ground or rising through the foundation from the soil. Those are separate risks with their own options, explained on the flood insurance page.
02 / Get ready
Bring this, and expect these questions
Gather
- Your current declarations page, showing whether sewer backup is listed and the limit beside it
- A rough rebuild figure for the finished basement: flooring, walls, ceiling, bathroom, bar or built-ins
- A list of what is stored or kept below grade, including appliances such as a freezer or second fridge
- The plumber's invoice or permit for any backwater valve, with the install date and the last cleaning
- Sump pump age, where the pit is, and whether it has a battery backup or a high-water alarm
- Where the downspouts discharge, and whether any are still connected to the weeping tile
- Dates and causes of any past water in the basement, with claim numbers if a claim was made
- Any camera inspection report of the sewer line, showing roots, sags or cracks
- Whether the basement is rented to a tenant or used for a home business
A broker will ask
- Does the current policy include sewer backup, and what limit and deductible apply to it?
- How much of the basement is finished, and what would it cost to redo?
- Is there a backwater valve on the main line, and who last serviced it?
- Where does the sump discharge, and what happens to the pump in a power cut?
- Has water ever come up through a floor drain, toilet or shower at this address?
- Have neighbours on the street had backups in the same storms?
- Is the basement lived in, rented or used mainly for storage?
- Has the sewer line from the house to the street ever been scoped or repaired?
Not sure of an answer? Leave it. "Not known yet" is a fine answer, and a broker will help you fill it in.
03 / Build your request
Answer a few questions. Get your own list.
Pick what fits. Your answers shape the list beside them, and they are saved to your request as plain facts a broker can read. "Not sure yet" is always a fine answer.
04 / Three situations
See which one sounds like yours
A buyer whose inspector found no backwater valve
A buyer is purchasing a 1950s bungalow with a fully developed basement, including a bedroom and a three-piece bathroom. The home inspector noted a floor drain and no backwater valve, and the seller mentions the street has backed up before.
First steps. Ask the seller for any claim history and the dates of past backups, and get a plumber's quote for a backwater valve, including whether a permit is needed. Give the broker the basement details and the quote, and ask which insurers offer backup cover before and after the valve goes in.
A family whose sump pump stopped in a power outage
A spring storm knocked out power for most of an evening in a newer subdivision. The sump pump stopped, water rose out of the pit and soaked new carpet and a sectional sofa. The family has backup cover but is unsure the pump failure counts.
First steps. Photograph the pit, the water line on the walls and the damaged items, and start drying right away to limit mould. Call the broker or insurer before throwing anything out, and ask how the wording treats water from a sump when the pump stopped because the power went out.
A homeowner with tree roots in the sewer line
Toilets in a 1960s house gurgle and the basement floor drain backs up slightly every few weeks. A plumber's camera shows tree roots through a joint in the clay line under the front lawn, on the owner's side of the property line.
First steps. Keep the camera footage and the plumber's written findings, and ask for a quote to repair or line the pipe. Ask the broker whether the backup endorsement responds to damage inside the house, whether a service line option would pay for the pipe itself, and how a known, ongoing problem is viewed.
05 / Words you will hear
The jargon, in plain words
- Backup endorsement
- An addition to a home policy that extends it to water and sewage pushed back into the house through its own plumbing. It normally comes with a separate limit.
- Cleanout
- An access point on the sewer line, often a capped opening in the basement floor, used to clear blockages and to inspect a backwater valve.
- Weeping tile
- A perforated pipe around the foundation footing that collects groundwater and carries it to a sump or, in some older homes, into the sewer.
- Sewer lateral
- The pipe carrying wastewater from the house to the municipal main under the street. Part of it usually sits on private property and is the owner's to maintain.
- Combined sewer
- An older system in which one pipe carries both storm runoff and household wastewater. Heavy rain can overload it and push water back toward homes.
06 / Common mistakes
What trips people up
- Reading water damage on the policy summary and assuming it includes water from a floor drain.
- Keeping a backup limit set years ago, before the basement became a family room, office and guest room.
- Installing a backwater valve and never opening the cleanout cover to check that the flap moves freely.
- Running the dishwasher or laundry while a backwater valve is closed during a storm, which can send water into your own basement.
- Throwing away soaked items before the insurer has seen photos of them.
- Treating a slow, recurring drain problem as something to claim later instead of having the line repaired.
Ready when you are
Turn this into one clear request.
Save it, add what you know, and choose when to send it. A licensed broker who handles sewer backup insurance takes it from there.
07 / Questions people ask
Straight answers
Is sewer backup covered by home insurance?
Not by default on most Canadian home policies. Backup through drains is commonly an optional endorsement added for an extra premium, and some insurers include it only in certain packages. Look for the words sewer backup, water backup or drain backup on the declarations page, with a limit next to them. If nothing is listed, ask the broker whether it can be added and what the insurer would want to see first.
How much sewer backup coverage do I need?
There is no standard figure. Start with what it would cost to restore the basement after a backup: removing and replacing flooring, lower drywall and insulation, cabinets and a bathroom, plus cleaning and drying. Add the belongings kept down there. Compare that total with the limits on offer. A broker can show which limits are available at your address and how each one changes the price.
Does a backwater valve lower my insurance?
It can help. Some insurers offer backup cover only once a valve is installed, others take it into account in pricing or limits, and a few may not change anything. What they look for is proof: a plumber's invoice, a permit where one is required, and a record of maintenance. Ask the broker how each insurer treats a valve and which document it wants to see.
Will the city pay if the sewer backs up into my basement?
Usually your own policy is the first place to look. A municipality is generally responsible only where it was negligent, and claims against a city follow their own process and may have short notice deadlines. Some municipalities have offered subsidy or rebate programs toward backwater valves, sump pumps or downspout disconnection. Whether one exists where you live, and its rules, varies by city and changes over time, so check your municipality's website.
What is the difference between sewer backup and flood cover?
The difference is the route the water takes. Backup arrives through the plumbing, pushed up by an overloaded sewer or a blocked line. Overland water arrives from outside, across the ground. A single heavy rainfall can cause both, and an adjuster will look at where the water entered. Because the two are usually separate endorsements with separate limits, having one does not mean you have the other.
Will a sewer backup claim affect my renewal?
It can. Insurers often ask what has changed since a water claim, and repeated backups at one address may narrow the options or lower the limit offered. Showing that the cause was dealt with helps: a new backwater valve, a repaired line, a pump with battery backup or disconnected downspouts. Keep the invoices with the claim file and bring them to the broker before the renewal date.
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General information, not insurance advice. Broker.insure is a directory and request service: it is not an insurer and does not quote, bind or advise. Policy terms, availability and what is required where you live depend on your situation and on licensed professionals. Updated 2026-10-31.