It happens to everyone at some time. You’re happily enjoying a nice hot shower, just lathering up your hair and you hear that dreadful sound — someone is flushing the toilet. You quickly turn to panic mode because you know you’re about to be hit with a blast of hot water. Or, suddenly mid-shower the water turns ice cold. While you might quickly become irritated, the fact is that the responsibility actually lies with your plumbing. Why does water pressure affect the temperature of your shower water? The following information will help you understand the issues underlying your shower shock.

Why Do I Get a Blast of Scalding Water?

If your shower water temperature gets hot when the toilet is flushed, it’s a good sign that you have an outdated trunk and branch plumbing system that doesn’t regulate your water pressure properly. In order to meet the desired water temperature, your shower valve mixes cold and hot water. On the other hand, your toilet only uses cold water. When a toilet is flushed while the shower is running, it siphons cold water away in while the toilet refills, making the water coming out of your showerhead hotter.

Why Do I Get a Blast of Icy Water?

Just as your toilet operation affects water pressure, when a tap is open and running hot water elsewhere in your home, it can affect the temperature of your shower in reverse, delivering chilly water instead of hot. If someone turns on hot water in the kitchen, starts the dishwasher, or turns on the washing machine for a load of laundry, it siphons away hot water, lowering your shower temperature.

Water Temperature Solutions

Some shower temperature issues require a simple fix, while others may need the expertise of a plumbing professional. Here are some remedies to keep your water temperature consistent:

• Don’t flush the toilet while people are showering. While this is a simple solution, it’s fairly impractical when you have a large family unless you set a showering/flushing schedule.
• Adjust your toilet’s refill valve. Slowing down how quickly your toilet refills can reduce some temperature shock, but there are drawbacks such as increased refilling time, noise, and a less efficient flush. Additionally, you could reduce the amount of water your toilet uses by placing a jug of water or brick in the tank, but your best bet would be to install a low-flow toilet instead.
• Install a thermostatic mixing valve. A thermostatic mixing valve will monitor the hot and cold water pressure entering the showerhead. If cold water pressure drops due to toilet flushing, it drops the hot water pressure to keep the temperature constant.
• Fix your plumbing system. This is usually the best solution if your home is older and you are experiencing other plumbing issues. A plumbing professional can resolve temperature issues by widening the main plumbing trunk and/or installing a more sophisticated load balancing manifold.

Need More Plumbing Help?

For more information about how to eliminate shower temperature shock, or for answers to any other plumbing questions, call the plumbing professionals at Amanda Plumbing today!