Basement Flooding in Hamilton: Sewer Backup, Groundwater and the City’s Protective Plumbing Program

Work out which kind of flooding you have

Sewer backup arrives from below, at the floor drain, a basement toilet or a laundry standpipe, during or just after heavy rain, and it smells like sewage. The lower city’s combined sewers surcharge in short, intense storms, and a house on a low street near the harbour or the Chedoke and Red Hill valleys is most exposed. Groundwater arrives at the wall-floor joint, through cracks and window wells, most often on the mountain after a storm or in spring, and it is clear or muddy rather than foul. A failed private lateral shows up as slow drains and gurgling in dry weather.

Photograph where the water first appeared and when. That answer decides whether you are calling a plumber for a backwater valve, a waterproofer for drainage, or the City at 905-546-2489 about the connection.

The Protective Plumbing Program

The City of Hamilton’s Protective Plumbing Program contributes toward the cost of installing protective devices such as a backwater valve on the sanitary lateral, a sump pump with a pit, and disconnecting foundation drains from the sanitary sewer, at homes that meet its eligibility rules. The work must be done by a licensed plumber under a City plumbing permit and inspected, and the application follows the City’s process and timelines. Read the current program page before you sign a quote, because the eligible amounts and conditions change.

A backwater valve closes when the sewer surcharges so sewage cannot flow back into the house; while it is closed, nothing in the house drains, which is why plumbers say not to run water during a storm. A sump pump pumps groundwater from the foundation drain outside instead of into the sanitary sewer. Ask the plumber to quote the valve and the pump separately so you can see what each protects against.

• Eligibility confirmed on the City’s program page
• Licensed plumber and City plumbing permit number
• Camera inspection recording and locate
• Itemized invoice for valve, pump and labour
• Application submitted per the program’s timeline

Who owns which pipe

In Hamilton the owner is responsible for the sewer lateral on private property up to the property line, and the City for the section from the property line to the main. A camera inspection with a locate tells you which side a break or root blockage is on; if it is the City’s side, call the City, and if it is yours, the repair is yours. Keep the recording either way, because an insurer will want it for a sewer backup claim.

Sewer backup and overland water are usually separate add-ons on a Hamilton home policy, and insurers commonly ask whether a backwater valve is installed. Check both before the next storm, not after.

Mountain, lower city and older houses

Lower-city houses from the 1880s to 1920s often have clay or cast-iron laterals, no foundation drain at all, and stone or brick foundations that groundwater passes through. Waterproofing there is a bigger project than a sump pump, and a plumber, a waterproofer and sometimes a mason each have a part. Mountain and Stoney Creek houses from the 1960s onward usually have weeping tile that a sump pump can serve, and grading that a landscaper can correct.

Downspouts that discharge next to the foundation are the cheapest problem to fix in either part of the city. Extend them well away from the house before spending on anything underground.