How To Unclog Clogged Drains
Drains are pretty simple and diagnosing a problem is simple if you understand the drain, waste and vent (DWV) system. To diagnose the problem, understand the DWV system and then follow this explainer to narrow down the problem, and solution.
Caution: Please read our safety information before attempting any testing, maintenance or repairs.
Water flows down hill. The whole DWV system is built on this principle. Most drain systems are gravity flow systems. Each drain in your home travels down to a larger branch drain. All the branch drains connect to the main drain or sewer line. A large pipe leaves your home and leads to the city sewer or your own septic system. All of this is downhill, all the way to the sewer or septic. In some cases, a home's sewer line will be below the level of the city sewer, or a basement bathroom is below the home's main sewer line and so pump equipment must be used to move the waste out to the main sewer or septic.
Along with all the drain and waste pipes, there are some vent pipes integrated into the system. These vent pipes allow sewer gas to be vented out above your home where it can quickly mix with the air and dissipate. The vents also serve the important function of preventing a vacuum or siphon from occurring. If a vacuum occurs, the draining water slows down and then becomes more prone to clogging. A siphon can also pull the water in the drain traps, which will then allow sewer gas to enter your home.
Problem | Solution |
I smell a bad odor near a sink, shower, tub or toilet |
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Only one toilet or sink or shower or tub or appliance is backing up |
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More than one toilet or sink or shower or tub or appliance are backing up, in the same part of the home, but the rest of the drains in the home are working properly |
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More than one toilet or sink or shower or tub or appliance are backing up, in different parts of the home |
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Sewage is backing up into your home, way beyond just an overflowing toilet |
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