Sump pump installation and battery backup
A sump pump is the exit for water that collects under a house. Drains lead the water to a basin set in the low spot, and the pump lifts it out and sends it away from the foundation. In a crawl space it usually goes in before a liner. In a basement it is the end point of the interior drain.
The parts, and what each one does
- AThe basin sits below floor level so water drains into it. A lid keeps damp air and debris in check.
- BThe main pump runs on house power. A float switch starts it when the water rises.
- CA check valve stops water in the pipe from falling back into the basin when the pump shuts off.
- DThe discharge pipe carries the water out through the wall and well away from the house.
- EA second pump sits a little higher and takes over if the first fails or cannot keep up.
- FA battery and charger run the second pump when the power is out. Many sound an alarm.
Where the water ends up
This is the question most often skipped. A pipe that stops a few feet from the wall lets the water soak straight back toward the basin, and the pump cycles all night moving the same water. The line should end where the ground falls away from the house, on your own lot, without sending water across a pavement or into a neighbour's yard.
Rules on where pumped water may be released differ between the city, Northport and the county. Ask the company which rule applies at your address and have the discharge point written into the proposal.
Why the backup matters here
The storms that fill a sump basin are the same storms that bring down power lines. A pump with no power is a bucket with a hole in the wrong end. A battery backup is a second, smaller pump on its own float, fed by a battery that stays on charge.
Batteries age. Ask what kind is supplied, how you will know when it is weak, and what a replacement involves. If the house has a standby generator, say so, because that changes what backup you need.
In a crawl space
The basin goes at the low end of the crawl space, with shallow trenches or perforated pipe leading to it. If the space is later encapsulated, the liner is sealed to the basin lid so the pit is not an open pool of damp air under the floor.
The pump needs an outlet nearby. Ask whether one exists and, if not, who installs it.
Test it twice a year
Lift the lid and pour in a bucket of water. The float should rise, the pump should start, the water should drop and the pump should stop. Then unplug the main pump and repeat to see the backup do the same. Walk outside and check that water came out of the far end of the pipe.
If you would rather not, ask the company whether it offers a yearly check and what is looked at.
Ask before it goes in
- Where is the low point, and how do you know? The basin belongs where water already gathers.
- Where will the discharge end? Walk the route with them.
- Is there a check valve, and can it be reached? It is a wearing part.
- What tells me the pump has failed? An alarm you can hear indoors, or one that sends a message.
- How long will the backup run? The answer depends on the battery and on how fast water arrives. Ask for the maker's figures.
Sump pump questions
My pump runs constantly. Is it broken?
Perhaps not. A float stuck in the up position, a check valve that lets water fall back, or a discharge that ends too close to the house can each keep a healthy pump busy. It can also mean more groundwater than the pump was sized for. Have it looked at before the motor wears out.
Can the pump empty into a floor drain or the sewer?
Do not assume so. Ask the company where your local rules allow pumped groundwater to go, and get the answer in writing.
Do I need a pump if I am getting a liner?
Only if liquid water collects under the house. A crawl space that is merely humid needs the liner and dry air. One that puddles after rain needs somewhere for that water to go first.
Tell someone what you are seeing
Call and describe what is going on under the house or in the basement. You will be put through to an independent local waterproofing company that works in your part of Tuscaloosa County.
Calls may be recorded. The company pays this site for the introduction. See the referral disclosure.