There are several possible causes that would reduce the temperature of your hot water. Start with your water heater; what type do you have: If you have an electric water heater, it could be a defective lower element or the dip tub could be missing; or if you have a gas water heater, it most likely is the dip tube (see FAQs – Dip Tubes).
It is important to remember that in the winter months, the water coming into your pipes will be much colder. The remaining hot water in the tank is diluted (incoming cold water pushes out hot water). A change in shower heads can also impact the outflow temperature of your water. Only 2/3 of the water heater’s capacity is usable hot water – a 50 gallon tank would give approximately 33 gallons. If you have a showerhead that is limited to 2.5 gallons per minute (GPM), you would have 15-20 minutes until the temperature drops, but if you have 5GPM – you would only have 8-10 minutes of hot water.
Here are a couple of tests that you can do:
- Don’t use any hot water for at least 4 hours. In a 5 gallon bucket with a 160 degree minimum temperature thermometer, turn the hot water on and allow it to fill the bucket. The thermometer should be in the stream of the hot water flowing out. Record how many times you fill the 5 gallon bucket before the temperature drops by 20 degrees.
- To determine the GPM rate of your showerhead, hold the bucket up to the shower and have someone turn on the shower and fill the bucket for 30 seconds. Determine how much water is in the bucket. Double that amount to get you GPM. If the bucket fills 1/3 in 30seconds, consider switching your shower head to a low flow showerhead. This will not only stretch your hot water usage, but also conserve water.
Go to the section on Models to determine the age of the water heater. If the tank is more than 7-8 years of age; it may not be worth repairing the water heater, but rather replacing the water heater.