It’s really annoying when you’re in the shower and your hot water suddenly cuts off. I’m sure everyone has been there before, right?

It usually happens all of sudden with no warning – it can be so uncomfortable and frustrating!

Some people just can’t seem to get enough of their morning shower, but if you’re one such person who has felt like the hot water temperature in your bathroom is all over-the-place lately, then this article may help.

Why Does My Shower Water Keep Going Hot and Cold

If you’re like most of us, you probably turn the knobs in your shower stall to get the temperature just right before you hop in.

But if you find that in the midst of your shower that water turns either ice cold or scorching hot for no reason – well – that can be uncomfortable but also dangerous.

So, why is it doing that?

There are several reasons this could be happening.

  • A problem with the water heater
  • You are using the wrong type of showerhead
  • You are using an on-demand water heater
  • Water pressure problems
  • A problem with the shower cartridge
  • Blocked pipes

So, the solution to fixing the problem depends of course on what is causing the problem.

But oftentimes – our clients tell us that the water temperature in the shower changes when someone else in the house uses a sink or bathtub or runs an appliance like the dishwasher or washing machine or even flushes the toilet.

The reason this is happening is more than likely that the hot water heater is not able to provide hot water to everything at once.

So, if you are taking a shower and then someone starts washing the dishes in the kitchen sink, your hot water heater then starts sending hot water to the kitchen sink. This lowers the water pressure in the hot water pipes to the shower and that’s when you feel that rush of cold water.

How Do You Keep The Water Temperature Constant In The Shower

The solution to keeping the temperature in the shower steady is to fix any of the problems that you may be having that we listed above.

A professional plumber can help to identify what the problem may be (or if it’s more than one) and then fix it so that you can get back to enjoying your shower time.

So, let’s go through each one of these problems for more information.

How to Fix Fluctuating Shower Water Temperatures

Any one of these issues we’re listing below can be the cause of the problems you are having with the water temperature in your shower fluctuating from hot to cold and sometimes back again.

Hot Water Heater Problems

One of the first areas to look at is the hot water heater in the house. The problems could be…

  • Water heater tank size – the heater unit itself may not be big enough for the demands that are being placed on it.
  • Water heater thermostat problem – if the thermostat on the water heater is malfunctioning or has tripped, then there’s nothing to regulate the temperature of the water.
  • Circuit breaker to the water heater tripped – it can certainly happen that the circuit breaker connected to the water heater tripped making the water heater malfunction.

Type Of Showerhead Matters

Many older homes have showerheads that use up to 10 GPM (gallons of water per minute) whereas the newer showerheads today use 2.5 GPM. If your using an older showerhead, you may be running out of hot water much faster than if you were using a newer model.

By the way, switching to a newer showerhead will also save you money on your water bill!

On-Demand Water Heaters

Tankless water heaters are on-demand water heaters. This means that they produce the hot water when it’s requested.

Because hot water is delivered directly on an as needed basis – the unit cannot produce hot water for multiple units at once. So, taking a hot shower AND running the washing machine may only give you lukewarm water. To avoid this you must purchase the proper size unit for your needs.

Or you can add a mini-mixing tank to your hot water plumbing system.

Speak to your plumber about your options.

Water Pressure Problems

You can fix water pressure problems in the shower with either a pressure-balance shower valve or a thermostatic shower valve.

Shower Cartridge Problems

Shower cartridges are located in the handle of your shower wall. They are used to regulate the water flow to your shower head.

Replacing the shower cartridge would be the solution to fix this problem.

Blocked Pipes

Your water heater or your vent pipes may have developed some corrosion or a blockage and these could cause your shower water temperature to fluctuate from hot to cold and vice versa.

The solution of course is to locate the blockage and clean them out.

Fixing any of these issues should solve your problems with your shower’s water temperature.


If you have any questions about shower water or are having some problems with it, call Atlantis Plumbing today at 770-505-8570. We are available 24 hours a day, 7 days a week.