BACKFEB 25, 2026
Stepping into a shower that is unexpectedly freezing—or worse, dangerously scalding—is one of the most jarring experiences of homeownership. It immediately triggers worry: Is the water heater broken? Do I need to replace the whole unit? How much will this cost?
Looking for more guidance? Take a look at our Repairs overview.
Take a deep breath. While water temperature issues are inconvenient, they don't always mean your water heater is dead. Often, the problem is a simple setting that drifted, a pilot light that went out, or a tripped breaker.
In this guide, we will help you isolate the problem. We’ll start by checking if the issue is with a single faucet or the whole house, and then walk through the specific adjustments for your type of water heater.
Before you grab a wrench, let’s look at what the water is telling you.
This is the most critical diagnostic step. Go to a different room and turn on the hot water.
If the water is fine in the kitchen but cold in the shower: The problem is local. You likely have a mixing valve issue or a clogged aerator at that specific fixture.
If the water temperature is wrong everywhere: The issue is at the source—your water heater. Proceed to the steps below based on what kind of heater you have.
Look at your unit.
Find your type below for specific instructions.
If the water is too hot:
If the water is too cold:
If the water is too hot:
If the water is too cold:
If the water is too hot:
If the water is too cold:
Solar systems usually have a "mixing valve" (or tempering valve) on the pipes near the storage tank. This valve mixes scalding solar-heated water with cold water to make it safe.
Diagnosing these issues is usually free and fast. If you need repairs, here is what to expect:
If you've adjusted the settings and reset the breakers but the water temperature is still erratic, it's time to stop troubleshooting and bring in help. Water heaters involve high voltage, gas lines, and pressure vessels—if the simple fixes don't work, the risks of DIY repair outweigh the savings.
Keeping track of when you last flushed your tank or checked the anode rod can prevent these surprises. For help organizing your home maintenance history and reminders for simple checks like these, download the Casa app. It’s a great way to stay ahead of repairs so you aren't left taking a cold shower.
