What size ejector pump do I need for a basement?

Ejector pump sizing depends on several factors specific to your basement setup, and getting it right is critical for a properly functioning basement bathroom.

The key sizing factors are the number of fixtures you're connecting, the vertical lift required (how far the waste needs to travel up to your main drain line), and the horizontal run distance to the sewer connection.

For a typical basement bathroom with a toilet, sink, and shower, a 4/10 horsepower (HP) ejector pump is the most common choice for residential applications. This handles the standard fixture load and typical lift heights of 10-15 feet. If you're adding a laundry sink or additional fixtures, a 1/2 HP pump provides more capacity and is often the better long-term investment.

Lift height is the most important variable. Most residential ejector pumps are rated for a maximum vertical lift of around 15-20 feet. If your basement is unusually deep or your main drain connection is higher than average, you'll need to confirm the pump's rated lift capacity matches your specific conditions. The pump must also handle the discharge pipe diameter — typically 2" for a standard basement bathroom setup.

On the Ottawa market, ejector pump systems including the pit, pump, check valve, and vent connection typically run $800 - $2,000 installed as part of a basement bathroom rough-in. The pump unit itself is $200 - $600 depending on brand and HP rating.

One important note: because ejector pump installation involves cutting into your drain stack and connecting to your home's plumbing system, it requires a plumbing permit in Ottawa. This isn't a DIY project — improper venting or check valve installation can cause sewer gas to enter your home, which is a serious health hazard.

For a proper sizing recommendation, a licensed plumber needs to assess your specific basement depth, fixture count, and drain line location. If you're planning a basement bathroom, Ottawa Bathrooms offers free consultations and handles all permits as part of the project.