Installing a sewage check valve, commonly known as a backwater valve, helps prevent basement flooding and backup from public sewers. A sewage check valve contains a one-way flapper that automatically closes to prevent backups. Houses containing a drain less than two feet above the nearest upstream sanitary sewer manhole cover are especially vulnerable to sewage backups. Installing the valve is a somewhat complicated task that is best performed by a professional plumber.
Things You'll Need
- Vernier calipers
- Eye protection
- Leather work gloves
- Ear plugs
- Dust mask
- Pipe cutters
Acquire any necessary building or plumbing permits from your local government. The city may require a plumbing inspection before granting a permit. Turn off the main water supply in the house.
Locate the floor drain in your basement, which is usually near the furnace or in the utility room.
Measure the interior diameter of the pipe under the floor drain with vernier calipers. Place the inside jaws of the vernier calipers inside the pipe, turn the knob until the jaws expand to the size of the pipe and read the measurement from the caliper's scale. This measurement will determine what size sewage check valve you need.
Break through the basement's concrete floor with a jackhammer and dig down to the sewer lateral pipe, which is near the floor drain. The lateral carries sewage from your house to the city's sewer main.
Cut out a section of the sewer lateral with pipe cutters. The area needs to be approximately the size of the sewage check valve.
Insert the sewage check valve into the pipe opening and secure it according to the manufacturer's instructions.
Attach any extra piping necessary to replace the pipe section you cut out.
Pour water through the valve to make sure it's draining properly.
Fill in the hole around the valve with cement or the material that was there previously. Turn on the house main water supply.
Clean the sewage check valve periodically, removing any stuck debris.
Tips & Warnings
- Consult your local building codes for any relevant rules regarding plumbing work and installation of a sewage check valve.
- For some sewage systems you may need to disconnect the weeping tile from the sanitary sewer and add a sump pit and sump pump prior to installing a sewage check valve.
- Wear proper safety equipment while operating a jackhammer.