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From A.B. May
Call Your Service Tech
From A.B. May

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How Does a Plumbing Trap (P-Trap) Lose Water?

Plumbing traps, commonly called P-traps, are an important part of your plumbing system. They are designed to constantly hold water in the drain to prevent sewer gas from escaping into the house. While sewer gases may contain noxious odors and smell terrible, they can also be explosive and poisonous. Ensuring that your P-trap has enough water will keep things running smoothly. Sometimes things start to run dry.

Top Reasons Why a P-Trap Would Leak

Here are some ways that your plumbing trap can lose water:



Overly dry air conditions can cause the water in your plumbing trap to evaporate.

Capillary Action

If something is stuck inside of the pipe and is wicking or absorbing the water from the toilet, capillary action could be to blame.


Traps can lose their water from too much wind and the air outside of the house, which could be getting into the pipes and may bounce the water out of the bowl.


An S-trap could also be the culprit of an empty trap. The long leg of the pipe causes the water to pass through with too much force, pulling water right out of the trap.

To learn more about the causes of an empty P-trap, take a look at this video.

How Long Does It Take for a P-Trap to Dry Out?

P-traps can dry out as quickly as a month, sometimes even less than that. This happens most often in winter. To prevent your P-trap from drying out, run the sink or shower for a minute or two once a week to keep water flowing and your P-traps from drying out.

Are you having an issue with your P-trap running dry? Do you think a clogged drain or one of the issues above could be to blame? Whatever your plumbing needs are, the experts at A.B. May are here to help! Our certified, skilled plumbers will arrive in a clean white truck, fully stocked with parts. We also offer 24/7 emergency service to ensure you never go without the help you need. To schedule a service visit, give us a call at 913-383-3100.

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