Adventures in Below Ground Plumbing - The Lift Pump

I’ve now owned a few different homes over the years but my current home is the first one with a bathroom that is below ground level (in a finished basement). When you have a bathroom below ground level then your plumbing subsystem has to have a “lift pump”. A lift pump system consists of:

• A sump in the floor where sewage (water / the other stuff) collects
• A pump that lifts the sewage up to the ground level where it can flow into the street level outflow

Note: A lift pump has a duty cycle of 8 to 10 years. A lift pump has a replacement price of approximately $1,500 so these things are expensive.

Things You Can’t Flush with a Lift Pump

You can’t flush:

• Kitty Litter
• Flushable Wipes

How to Know When You Have a Problem with your Lift Pump

Here are three symptoms of failure:

• Smell. A bad lift pump reveals itself with a fairly rank odor in the lower region of the house centered around the machinery room where the lift pump is located.
• Leakage. Leakage from the sealed sump where the lift pump is located.
• Noise. Many lift pump systems will have an alarm on them that beeps when there is an issue.

Two Ways to Fix a Difficult Lift Pump

There are at least two failure symptoms with a lift pump:

• Pump doesn’t work at all (no noise when you power cycle it)
• Pump works but you can’t flush a toilet / have water backup / sump leakage

Here are two approaches to fixing the second:

• Turn it off and let it sit for a number of days. Just as a clogged toilet will magically “fix” itself when left alone, so too will a lift pump that is clogged. The blockage often dissolves.
• Lift the Vertical Pipe up and down and “shake” it. The lift pump itself is directly coupled to the vertical pipe and if you lift it up and down / shaking it, you can often dislodge the blockage.

Thank You

I learned all of this from David, a technician at Benjamin Franklin Plumbing who serviced my house today. The $49 for the service call for him to tell me this much was much, much preferable to the $1500 fee for a new lift pump.