At the end of a long day, you deserve a nice, relaxing shower. You turn on the faucet, carefully adjust the knobs, and you wait for the perfect temperature. The steamy air immediately relaxes your muscles, and you look forward to a good soak.

But not long after you hop in, the water shifts from blissfully warm to shockingly cold. In just a few seconds, your water feels comparable to Antarctic glacial meltwater instead of a Finnish sauna. In frustration, you turn off the water and shiver violently as you towel yourself off.

Your shower was going so perfectly. What went wrong?

1. Your Dip Tube Has a Crack

If you have a traditional water heater with a tank, your unit likely features a part known as a dip tube. The dip tube travels through an inlet in your water heater and stops a few inches above the bottom of the tank.

The dip tube directs incoming cold water to the bottom of the heater, bringing it close to the heating elements. Without a dip tube (or with a damaged dip tube), the incoming cold water would simply mix with the hot water, resulting in lukewarm temperatures.

Check your shower head, faucet aerators, and appliance filters for small bits of plastic. These broken pieces often indicate that your dip tube has broken and disintegrated.

While you’re examining your plumbing, check the date of your water heater. Many heaters built between 1993 and 1996 have a defective polypropylene dip tube, and you’ll want to have an expert install a replacement unit.

2. Your Water Heater Tank Is Too Small

The average household relies on a water heater with a 50-gallon tank. As a result, you can use up to 50 gallons at any time before you have to wait for your water heater to warm its supply.

The average shower has a flow rate of about 2.1 gallons per minute, which means you can enjoy your hot water for at least 23 minutes before you’ll feel the cold water leak in.

However, multiple factors could affect how long your hot water actually lasts. If you have another appliance running, if a family member recently showered, if you have a smaller 30- or 40-gallon tank, or if you have a high-flow faucet, you might not have enough hot water to go around.

If you regularly find yourself shivering in the shower, you may need to upgrade to a bigger tank to accommodate your needs.

3. Your Tankless Heater Needs a Mixing Tank

If you want to cut your hot water heating costs, or if you want to avoid cold showers altogether, you and your family may install a tankless water heater. Tankless water heaters don’t store water but rather heat it on demand, so you have a seemingly endless supply.

But tankless heaters have their shortcomings. Once the burner switches off, any water still in the line will cool. When you turn the faucet on again, that cold water will flush through the line alongside your hot water, giving you a sandwich of fluctuating temperatures.

You can solve this problem by hiring a plumber to install a mini-mixing tank with your tankless heater. This smaller 2- to 6-gallon tank does not store massive amounts of water like traditional water heaters. Instead, it holds some of the water back from your line, allowing the cold water to blend with the hot water more thoroughly, so you have a constant temperature.

Enjoy Warmer, More Consistent Showers

Although the above reasons could explain why your showers seem inconsistent and disappointing, keep in mind that your particular plumbing could have an underlying issue not listed here. For example, you may need a pressure balancing valve if your shower changes temperatures whenever someone flushes the toilet. Or you might need a thermostatic valve so you can set your precise temperature before you step foot in the shower.

Call in a professional plumber to inspect your pipes and valves and determine what’s affecting your water temperature.