How Do You Fix a Hot Shower When the Toilet Is Flushed

A plumbing issue is not always a simple fix. If you have noticed that your hot water has been running cold, or if you are trying to take a hot shower and the water seems to get colder when the toilet is flushed, then this post will help explain how you fix a hot shower when the toilet is flushed even with minimal DIY skills. 

The problem might be that there needs to be more air pressure in the pipes, which can often happen after new fixtures are installed or an appliance like a dishwasher is added. But before you call for repairs, read on! This blog post will show how easy it can be to increase air pressure in your pipes by adding an air admittance valve (AAV). So follow these instructions and enjoy nice warm showers again.

How Do You Fix a Hot Shower When the Toilet Is Flushed

Reasons Why You Should Fix a Hot Shower When the Toilet Is Flushed:

So you are enjoying your hot shower, the steam filling up the room, relaxing your body and mind. Suddenly, the sound of drained water fills your ears as you feel a slight draft where there was once warmth. You have just been hit with cold water after flushing the toilet!

This is very frustrating and generally disgusting because not only is your shower cold now, but the toilet has just flushed all of the water that was currently in it down the drain! This can be fixed if you know how to fix a hot shower when the toilet is flushed.

This problem is usually caused when the tank is refilled with cold water. This is usually due to a faulty mixing valve or a faulty thermostat. A mixing valve mixes the incoming hot and cold water so that when you turn on your faucets, you receive a nice mix of warm and cold water to adjust to your desired heat level. A faulty mixing valve can often be fixed by adjusting the screw on top of it or replacing it if necessary.

Directions: How Do You Fix a Hot Shower When the Toilet Is Flushed

Unfortunately, plumbing is a vast topic and requires much-specialized knowledge not included in this article. However, here are some essential tips for repairing your water heater when it flushes out your shower.

Step 1:Determine if This Is a Plumbing Issue or an Electrical One

If the water heater is leaking, it’s a plumbing problem. If the breaker panel is tripping or there are other electrical issues (lights flickering, for example), it may be an electrical problem.

Step 2: Call a Plumber if You Can’t Fix It Yourself

If you’re not a plumber, don’t troubleshoot to the point of causing more damage. Call your local plumber and explain the problem.

Directions to  Do You Fix a Hot Shower

Step 3: Check for Leaks or Blockages in the Tank.

With the water turned off at the breaker panel, remove all the wires from the water heater. Next, turn on the cold water to fill the tank, and wait for it to heat up. Then examine the bottom of your tank for leaks or cracks. If everything’s dry, reattach the wires and turn off the breaker panel again.

Step 4: Check the Pilot Light.

If you have a gas-powered water heater, check that the pilot light is lit and not stuck or blown out. If it is burned out, relight it using a match and air it out for about 5 minutes before turning on the breaker panel again.

Step 5: Turn Everything Back on and Enjoy Your Shower.

Turn on the breaker panel and enjoy your shower if everything is working. If you still have problems, contact a local plumber to check for other issues before it leads to future damage or more costly repairs.

Things to Consider Before Fixing a Hot Shower:

1) Purchase an air admittance valve (AAV). You can purchase this item at any plumbing supply store, many hardware stores, or even online. This specific AAV is manufactured by Greenheck for 0 to 1-inch copper pipe and costs less than $30.

2) Shut off the cold water supply line that feeds the shower.

3) Shut off the gas or electricity to your home if at all possible. Again, this should only be done by a trained professional. If you cannot shut off the gas or electricity, do not further call a licensed plumber and avoid potential injury!

4) Drain water from the line. Again, this step is usually best for a wet/dry vacuum.

Drain Water From the Line

5) Remove the P-trap to access the water lines supplying your shower. The trap can be difficult to remove. You will need to use adjustable pliers to break the lock rings loose under stress because these are compression fittings usually locked in place with rubber rings. The water in the P-trap will likely come rushing out when this is done, so be prepared for it.

6) Remove the compression nuts on both sides of the shower arm using adjustable pliers. Be careful not to drop any parts into the wall or cabinet next to your shower, including these nuts and washers.

7) Pull the shower arm out of the wall and inspect it. You can clean or replace any corroded parts for maintenance or help with your repair if needed. For example, if your shower is plumbed with PEX tubing, remove the compression nuts, pull out the entire length of PEX tubing, and then remove all of the compression nuts on the water supply lines at the house shutoff valves.


There are many reasons why your hot shower isn’t coming out as warm or hot. If the water pressure is low, you may need to call a plumber for this issue. The temperature of the tankless heater can also be altered by adjusting its thermostat.

Most importantly, if any other plumbing work is done in your home recently that needs repairs, these should be prioritized before fixing anything else! For example, we hope now you understand how you fix a hot shower when the toilet is flushed. If there is anything you want to know, then feel free to contact us!

Angela Ervin

Angela Ervin

Angela is the executive editor of DIY quickly. She began her career as an interior designer before applying her strategic and creative passion to lifestyle and home. She has close to 15 years of experience in creative writing and online content strategy for housekeeping, home decorations as well as other niche efforts. She loves her job and has the privilege of working with an extraordinary team. She lives with her husband, two sons, and daughter in Petersburg. When she's not busy working she spent time with her family.

We will be happy to hear your thoughts

Leave a reply

DIY Quickly