The black pipes you see under your sink and in the basement are made with a plastic called acrylonitrile butadiene styrene, or ABS. Plumbers use them exclusively for drain waste vent systems. Their advantage over PVC in this regard is their superior flexibility and resistance to extreme temperatures. Waste lines aren't pressurized, so when a length of ABS pipe leaks, it's usually either because a joint wasn't glued properly or the pipe is under external stress. Because they are used for waste lines, leaks in ABS pipes are often accompanied by sewer odors, so prompt attention is in order.
Determine which plumbing fixtures are serviced by the ABS pipe you will repair and make sure no one uses those fixtures while you're working.
Locate the leak and plan a strategy. If the leak is coming from a fitting, you may need to reglue or replace the fitting. If it's coming from a length of pipe, you'll need to cut out the damaged pipe and replace it.
Pull apart a loose joint and re-glue it. Because waste lines aren't pressurized, plumbers often dry-fit ABS pipes and then forget to glue them. Clean both sides of the joint with a rag, then spread an even coat of ABS glue on both sides with the applicator that comes in the glue can and fit the joint together. The glue sets in about 20 seconds.
Replace a fitting if you see a crack in it or notice water seeping from it. To replace the fitting, you'll have to cut it out of the line.
Cut through the pipes on each side of the fitting about 1 or 2 feet away from it with a hacksaw. Measure the distance from each of the cut-off pipes to the location of the fitting with a tape measure and cut new lengths of ABS pipe to those measurements.
Deburr the end of the pipe with 120-grit sandpaper. Spread ABS cement on the inside of the coupling and on the end of the pipe, then push the coupling onto the pipe, making sure at least 1/2 inch of pipe is inside the fitting. Give it a little twist to spread the glue evenly. Glue the new pipes to the couplings, then join the pipes at the location of the damaged fitting by gluing them to a new, identical fitting.
Repair a leaking pipe by cutting out the damaged section with a hacksaw. Glue couplings to each end of the pipes that remain, measure the distance between the couplings and cut a length of new pipe to that measurement. Glue it to the couplings with ABS cement.
Things You Will Need
- ABS pipe cement
- Tape measure
- 120-grit sandpaper
- ABS couplings
- ABS pipe
- Use ABS or multipurpose cement to glue ABS pipe. Avoid PVC cement. It won't adhere properly. Work quickly once you've spread the glue.
- Your only indication of a leak in an ABS vent line may be sewer odor. You'll probably have to inspect the pipe around the general location of the odor with a flashlight to find the leak.
- Your local government may require you to obtain a plumbing permit if your repair involves cutting into or removing pipe, so check with your county or municipality to get a permit, if necessary. Failure to do so could result in a fine and/or a requirement to tear out the work that you did.
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