Why Is My Shower Going Hot and Cold?

Why Is My Shower Going Hot and Cold?

Have you ever experienced the frustration of stepping into a shower only to be greeted with alternating bursts of scalding hot and icy cold water?

The inconsistency in shower temperature can be not only uncomfortable but also a cause for concern.

In this article, we will delve into the various factors that can lead to a shower going hot and cold, exploring the causes, troubleshooting techniques, and potential solutions to help you regain control over your showering experience.

Understanding Inconsistent Shower Temperature

Fluctuating Water Temperature in the Shower

One of the most common issues people encounter is a shower with fluctuating water temperature. You might find yourself adjusting the shower dial frequently as the water oscillates between extremes. Several underlying causes can contribute to this frustrating problem:

Shower Mixing Valve Problems

The mixing valve in your shower plays a crucial role in blending hot and cold water to achieve the desired temperature. Over time, these valves can develop issues such as wear and tear, mineral deposits, or internal component failure, leading to inconsistent water temperature. Replacing or repairing the mixing valve may be necessary to restore stability.

Water Pressure and Shower Temperature

Water pressure imbalances can also result in hot and cold fluctuations. If your shower relies on a combination boiler system, changes in pressure due to water usage elsewhere in the house can affect the temperature. A drop in pressure might cause the shower to become hotter, while increased pressure could lead to colder water. Ensuring balanced water pressure throughout your plumbing system can help alleviate this problem.

Shower Thermostat Issues

Faulty thermostatic controls can cause temperature irregularities. Thermostatic mixing valves are designed to maintain a constant water temperature by blending hot and cold water. If the thermostat is malfunctioning, it may fail to accurately regulate the water temperature, leading to unpredictable fluctuations. Inspecting and recalibrating the thermostat or replacing the faulty component can help resolve this issue.

Thermal Shock in the Shower

Another possible explanation for the sudden changes in water temperature is thermal shock. This occurs when there is a rapid transition between hot and cold water, such as when a toilet is flushed or another tap is turned on while you are in the shower. The sudden influx of cold water can disrupt the balance, causing the shower to become scalding hot temporarily. Upgrading to a thermostatic shower valve that maintains a stable temperature despite fluctuations in the water supply can mitigate thermal shock.

Crossflow Between Hot and Cold Water in the Shower

Crossflow refers to the unwanted mixing of hot and cold water within the plumbing system. It can occur when there is a malfunction in the shower diverter, shower cartridge, or other components responsible for controlling water flow. Crossflow can lead to temperature spikes, causing your shower to alternate between hot and cold. Replacing faulty parts or seeking professional plumbing assistance can help rectify this issue.

Sediment Buildup and Shower Temperature

Over time, sediments and mineral deposits can accumulate in your showerhead, pipes, or mixing valves. These deposits can restrict the flow of water and interfere with the proper functioning of temperature controls. Flushing out the plumbing system, descaling the showerhead, or cleaning the mixing valves can help remove sediments and restore the desired water temperature.

Troubleshooting Shower Temperature

When faced with hot and cold water issues in your shower, there are several troubleshooting steps you can take before resorting to professional assistance. Here are some tips to help you regain control over your shower temperature:

  1. Check for Water Heater Problems: Ensure that your water heater is functioning properly. If it is an older model, consider flushing it to remove sediment buildup that could impact water temperature.
  2. Inspect Mixing Valve and Thermostat: Examine the mixing valve and thermostat for any visible damage or signs of malfunction. Clean or replace these components as necessary.
  3. Balance Water Pressure: Check the water pressure throughout your plumbing system to ensure it is balanced. Adjustments may be required to avoid pressure fluctuations that affect shower temperature.
  4. Remove Sediment from Showerhead: If you notice reduced flow or temperature inconsistencies, remove the showerhead and clean it thoroughly to remove any accumulated sediment.
  5. Consider a Pressure-Balancing Valve: Installing a pressure-balancing valve can help stabilize water temperature by compensating for pressure changes within the plumbing system.

Remember, if these troubleshooting steps do not resolve the issue or if you are uncomfortable performing them yourself, it is advisable to consult a professional plumber for a comprehensive evaluation and repair.


Why does my shower go from hot to cold and vice versa?

Fluctuating water temperature in the shower can be caused by various factors such as shower mixing valve problems, water pressure imbalances, faulty thermostats, thermal shock, or crossflow between hot and cold water. Identifying the specific issue will help determine the appropriate solution.

How can I fix a shower with an inconsistent temperature?

Start by checking for any visible problems with the mixing valve, thermostat, or showerhead. Clean or replace these components if necessary. Additionally, ensure balanced water pressure and consider installing a pressure-balancing valve. If troubleshooting steps do not resolve the issue, consult a professional plumber.

Can sediment buildup affect shower temperature?

Yes, sediment and mineral deposits in your showerhead, pipes, or mixing valves can restrict water flow and interfere with temperature regulation. Regularly cleaning and descaling these components can help prevent temperature fluctuations.

What is a thermal shock in the shower?

Thermal shock occurs when there is a sudden and drastic change in water temperature during a shower. It can happen when a toilet is flushed or when another tap is turned on, causing a temporary disruption in the hot and cold water balance.

When should I seek professional help for my shower temperature issues?

A: If you have attempted troubleshooting steps and the problem persists or if you are unsure about performing repairs yourself, it is recommended to contact a professional plumber. They can assess the situation, identify the underlying cause, and provide appropriate solutions.