You know the drill: when someone else is in the shower, you don’t flush the toilet. If you do, the person who is showering gets a face full of scalding hot (or cold) water. It’s unpleasant, painful, and probably due to your water pressure in your home. Here’s how it works:
How does water pressure affect your shower’s temperature?
Usually, plumbing is configured in a trunk and branch system. The water runs from one side of the building to the other in a large pipe, with small offshoot pipes that connect to different plumbing fixtures like your shower, washer, toilet, or sink. If you have lower water pressure in your home, when one fixture takes some of that water from the trunk pipe, it means there is less water for the rest of the fixtures. Sometimes, homes just have one water line for a shower, tub, and toilet in the same bathroom! So, when you flush the toilet, it needs water to fill up the tank. The toilet gets the water from the trunk pipe and, if you’re showering during this time the shower will have less cold water coming from the trunk pipe. Therefore, the shower’s temperature will heat up! Homes with this type of plumbing configuration may also have a shower’s temperature change when someone turns on the washing machine, the dishwasher, or even the sprinklers.
How to Prevent Your Shower from Scalding You When Someone Flushes the Toilet
The easiest way to prevent a scalding shower is to limit how fast water fills up the toilet tank. You can do this by closing the supply valve on the wall behind the toilet slightly. This will make the toilet tank fill more slowly and allow for more water pressure to accommodate the shower. Landmark Home Warranty doesn’t recommend placing a brick or other heavy object in the tank to decrease the amount of water used to fill up the tank. It may cause your toilet to overflow instead of flush or not get solid waste down the s-bend.
You can also install a pressure-balanced valve that will provide water at a constant temperature in your shower, regardless of if your water pressure changes in the hot or cold water lines. A pressure-balanced valve recognizes the drop in cold water when a toilet is flushed and makes sure to balance the pressure and temperature of both lines. The water temperature is the same, but the pressure of the water may be lessened. A plumber can install this type of valve in your plumbing system.
There are other solutions that you can explore, like increasing the diameter of the supply valve, or installing a new system, like a manifold. These solutions can be expensive and require major plumbing renovations. It’s easier to limit the supply of water filling up your toilet.
Home Warranties can Help Protect Your Plumbing
If you own a home, protect your plumbing with a home warranty plan from Landmark. Home warranties water heaters, toilets, pipe leaks, shower and tub valves, faucets, and many other parts of your plumbing system. If your plumbing fails, and you have a home warranty, call your home warranty company. They will send a trusted plumber to your home to diagnose and repair the problem for a service call fee. Of course, the plumbing failure has to have failed from normal wear and tear. Explore more about your home's plumbing with our plumbing articles.