How to Fix an Air Lock in a Sewer Line

Air locks in plumbing can render the pipes useless until the problem is fixed. Air locks can occur anywhere, and if all of your waste water flows into the sewer line, the problem may be in the sewer. The first thing you need to determine is where the airlock is. You may need to start with the sink, toilet or sump pump before going directly to the sewer line. Often an air lock is just in the hot water line. It is best to rule out possible locations before opening the sewer trap to clear an air lock in the sewer line.

Drainage pipe
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Make sure you know where the clean-out is to your sewer pipe.
Pedestal sink
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A piece of old garden hose works well to connect the two faucets.

Start at the sink. If your sink has separate hot and cold faucets, attach a length of hose to connect both taps. Open the hot tap first and then slowly turn on the cold. The cold water will flow into the hot water line and should push out the air lock. If your sink has only one faucet that mixes both hot and cold, place an absorbent cloth directly over the spout. Turn on the cold water slowly to force it back into the pipe. If this works, it will force the cold water into the hot water pipes and flush out the air lock. In either case, let the cold water run for up to two minutes and then let the hot water run for an additional two minutes to make sure the air lock is clear. If this does not correct the problem, move on to the toilet.

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A wet/dry vacuum can also be used to suck out the water.

Remove all the water from the toilet. This can be done by bailing it out and then absorbing the rest with a cloth. Disconnect the water supply. Pour water directly down the pipe. If it does not go down, go on to the sewer line. If it does go down but there is still blockage further down, go to your sump pump.

Step 3

Drill a small relief hole at an upward angle into the sump pump discharge hose if you suspect the problem may be there. Pour water into the sump crock to see if that corrects the problem. If not, move on to the sewer line.

Pipe wrench
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Lubricate your pipe wrench if it is difficult to adjust.

Locate your sewer line's clean-out trap. Place the bucket underneath to collect anything that may fall out. Use the pipe wrench to slowly open it. Remove any obstruction. Reattach the cap when cleared.

Step 5

Test the water throughout the house. If the air lock seems to be clear, leave the water running for several minutes to make sure. If there is still a problem, consult a plumber.