Why Your Shower Gets Hot When a Toilet Flushes
We’ve all been there, minding our own business taking a shower, when all of a sudden it turns burning hot. Come to find out, someone flushed the toilet. Why does your shower get hot when the toilet flushes? Shouldn’t that not happen?
Your Plumbing System
Most homes have a piping system that is a trunk and branch system. Branches go to each faucet, shower, toilet, etc. The trunk is what supplies water to the individual branches. There are two main trunks in the trunk and branch system. One is for hot water and the other is for cold. They run throughout your home. This design can have some issues which is why your shower gets hot when a toilet flushes.
Why Your Shower Gets Hot When a Toilet Flushes
When your shower suddenly changes temperature, that is due to the trunk pulling more water to the toilet’s branch to aid in flushing. Water will be taken away from the shower to help flush the toilet causing your shower temperature to change. It is generally cold water that is taken away when the toilet is flushed, therefore your shower gets hot when a toilet flushes.
Can You Fix This?
Now, there are two ways to fix your shower getting hotter when a toilet is flushed. One of them involves redoing the entire trunk and branch system. If this is what you choose to do, you will likely make the trunk bigger or make it more complex by adding more branches. This can become an expensive fix, you may also have to reinstall walls, flooring, or repaint.
There is a much cheaper and much easier fix that you can do. It is a thermostatic mixing valve. This is installed in your shower. So, how does the thermostatic valve keep your toilet from causing temperature changes in your shower? It will keep the pressure constant on both hot and cold water lines. This will balance your water temperature. If one goes down due to pressure loss the other will kick in.
You can also adjust the flow of water to your toilet to help this issue. However, your toilet will refill a lot slower. It might just be best to warn someone in the shower that you are going to flush or use the hot water.
Why is my Shower Getting Colder Not Hotter?
Well, what if your water turns colder instead of hotter? This can happen when you flush your toilet or use any other sort of appliance. It depends on what water source is being used, your dishwasher using hot water may pull the hot water away from the shower, leaving it colder. Luckily, there aren’t two separate fixes. You can either redo the branch and trunk-style plumbing to accommodate you or use the thermostatic valve.
Final Thoughts
There are three solutions to this issue, the first one is giving the person in the shower a heads up that you need to flush the toilet or use the sink. This way they can step out of the way until the water returns to normal. The other ways involve a plumber to adjust some things, by either installing a thermostatic valve or adjusting your trunk and branch system.
Call 1-Tom-Plumber
Don’t hesitate to contact us here or call us at 1-Tom-Plumber (1-866-758-6237) if you need help with any plumbing, drain cleaning, water damage, or excavation services. 1-Tom-Plumber’s certified team of plumbers and drain technicians respond immediately to any emergency plumbing, drain cleaning, or water damage problem. We also handle the excavation of underground water lines and sewer main lines. Our immediate-response team is available every day and night of the year, even on holidays.
