Hot Water Runs Out Fast? 5 Fixes, From a $20 Part to Going Tankless

Published 2026-07-27 · Straightline Plumbing and Guttering

If your shower turns cold after five minutes and the tank used to last twice as long, something changed inside the heater. Here are the causes in order of how often we see them in Delaware homes.

1. Sediment is eating your capacity

A few inches of mineral sediment at the bottom of a 50-gallon tank can turn it into a 35-gallon tank and insulate the burner or lower element from the water. A flush restores capacity if the tank is in decent shape.

2. Broken dip tube

The dip tube sends cold water to the bottom of the tank. When it cracks or crumbles (common on units made in the mid-1990s and on cheap replacements), cold water mixes at the top and you get lukewarm water quickly. It is a cheap part and a 30-minute repair.

3. A failed lower heating element (electric)

Electric heaters have two elements. When the lower one fails, only the top third of the tank heats, so hot water runs out fast. Element replacement is routine.

4. Thermostat set too low or failed

A thermostat stuck below 120°F gives you a full tank of not-quite-hot water. Easy to test and replace.

5. The tank is simply too small

Two teenagers and a soaking tub outgrow a 40-gallon heater. Options: a larger tank, a high-recovery gas unit, or a tankless water heater that never runs out. For most families in Lewes, we lay out all three prices and let you choose.

Same-day water heater help across Delaware

Straightline Plumbing and Guttering carries elements, dip tubes and thermostats on every truck and installs new tank and tankless units the same day. Call (888) 480-9811.