Your water is likely not getting hot enough due to a faulty heating element, a broken dip tube, heavy mineral sediment buildup inside your tank, or a flipped thermostat/high-temperature cutoff switch.
Low hot water is often caused by common water heater issues like a broken dip tube, sediment buildup, faulty thermostats or heating elements, and dry firing—all of which reduce heating efficiency.
As water collects inside your hot water heater to be heated, it's common for debris in the water—like sand, dirt, and minerals—to settle at the bottom of the tank. As the particles collect on the bottom of the tank, the water heater can't effectively heat your water, resulting in lukewarm water only.
This problem usually comes down to capacity, heat production, or mixing issues inside your plumbing system. Sometimes the fix is simple, like adjusting your water heater temperature or flushing out sediment. Other times you may need a new mixing valve, an element replacement, or a different size water heater.
Sediment build up in the tank
Over time, sediment can build up in the bottom of the tank, where the burner usually is. This can lead to slower heating or poor efficiency in your water heater, meaning lukewarm water rather than hot water. The solution for this is to drain the tank and to use a water softener.
Signs a Water Heater is Going Bad
A tap or shower that keeps switching between hot and cold water could be a sign that the heat exchanger inside a combi boiler is blocked. Sludge and sediment buildup is fairly common in older boilers, especially when the filters are old. This blockage will then cause water to run hot and cold intermittently.
Sediment buildup is one of the most common causes of hot water pressure being low, but cold is fine.
Water Heater Size
Your tank size is the most significant determinant of how long you can have a hot shower: 30-gallon tank: ~5–7 minutes of hot water. 40-gallon tank: ~8–10 minutes. 50-gallon tank: ~10–12 minutes.
To help us save every drop of water, showers should be kept to four minutes or less. Wondering if cutting a couple of minutes off your shower really helps? The answer is yes!
Circulating pump not working?
10. Water Isn't Getting Hot Enough (All Water Heaters)
Water Heater Lifespan
If your tank water heater is more than 10 years old, it may be time to consider replacing it. With proper maintenance, a tank water heater tank should last six to 12 years. A tankless water heater can last for more than 20 years. Check your water heater's warranty for the most accurate timelines.
The most common shower mixing valve problems include:
If a standard showerhead is fitted, it will use around an extra half a gallon each minute, accounting for a 25-gallon emittance every 10 minutes, or 50 gallons throughout a 20-minute shower. *1 gallon = 4.54 litres.
5 Signs Your Water Heater Is Going Bad (And What to Do About It)
If hot water runs out too soon, maybe the heater's too small, or it's slow to reheat, or there's buildup inside. You might notice water getting colder faster, or weaker pressure. There are ways to keep your supply steady, but let's look at some common questions.
Flushing your water supply lines can be done by turning off the main water supply, opening all taps, and letting water run until it's clear. This process helps remove any lingering sediment, ensuring optimal flow throughout your system.
Just take a can of WD-40 (preferably one with a long flexible hose) and spray it inside of your faucet. The WD-40 will loosen up the hard water and make the diverter work as smoothly as day one.
Signs of a clogged p trap drain:
A blocked or scaled plate heat exchanger is the number-one reason your hot water goes cold after a few minutes of good flow. The secondary plate heat exchanger transfers heat from the primary circuit to your incoming mains water.
The Rule of 120
A helpful guideline is the "Rule of 120": if the sum of the air temperature and water temperature is less than 120 degrees Fahrenheit, you should wear thermal protection like a wetsuit or drysuit. But even this rule has limitations - always dress for the water, not the air.
Resetting Your Hot Water System
Locate the power switch or button on your hot water system. It's usually near the unit or on the control panel. Turn off the power to your hot water system by flipping the switch or pressing the button. Wait for about 10-15 seconds, then turn the power back on.