Hot water running out before everyone's showered? Fix it before school starts.

If your water heater runs out of hot water faster than it used to, the usual causes are sediment taking up room in the tank, a broken dip tube mixing cold water into the hot, a failed lower element on an electric unit, or a tank that's too small for how your household uses water now. The first three are repairs. The last is a sizing question, and the number that answers it is printed on the yellow EnergyGuide label.

School starts August 31 in both Huron Valley and Novi, and that's the week a lot of water heaters get found out. All summer, showers are spread across the morning. Then it's four people in a row before 7:30, and whoever's last gets a cold one. A week ahead of that is a good time to figure out why.

Has it always been this way, or is it new?

Start with this question, because it splits the causes in two. If the hot water used to last and now it doesn't, something changed inside the tank, and it's usually fixable. If it's always run short when everyone showers back to back, the tank is doing its best and it's probably just too small for the household.

Sediment is taking up space

Minerals in the water settle to the bottom of the tank as sediment. Over the years that layer takes up room that used to hold hot water, and it insulates the water from the burner, so the tank recovers slower between showers. A rumbling or popping sound when it heats is the giveaway. It's worst on hard well water around Milford and Highland, which we cover in our hard water guide. A flush often helps, and we walk through it in how to flush your water heater.

A broken dip tube

Cold water enters the top of a tank water heater, but a plastic pipe called the dip tube carries it down to the bottom, so it doesn't mix with the hot water waiting at the top where it's drawn off. When the dip tube cracks or breaks off, cold water lands right where the hot water leaves. The tank is full of heated water, but you're getting it mixed with cold, so showers go lukewarm fast.

The clue is small white or gray plastic bits in your faucet aerators or showerhead, which are pieces of the tube breaking down. Replacing a dip tube is a repair, not a new water heater, but it's a job for a plumber.

Electric units: a failed lower element

An electric water heater has two heating elements, one near the top and one near the bottom. If the lower one fails, only the top part of the tank gets heated. You get a short burst of hot water and then it fades fast, which feels a lot like running out. Elements are a common repair. If you have no hot water at all rather than too little, our no hot water troubleshooting guide covers the checks to do first.

Or the tank is too small for your mornings

Tank size in gallons is only part of the story. The better number is the first hour rating, which is how many gallons of hot water the heater can deliver in an hour starting from a full, hot tank. It's printed at the top left of the yellow EnergyGuide label as "Capacity (first hour rating)." The Department of Energy's advice is to pick a water heater whose first hour rating at least matches your household's busiest hour.

So think about your busiest hour once school starts: every shower, plus the dishwasher or a load of laundry if those run at the same time. If that's clearly more than the tank can deliver, no repair will fix it. That's when it's worth looking at a larger tank or going tankless, which we compare in tankless vs tank in Michigan.

Quick wins for school mornings

• Space the showers out. Even 15 or 20 minutes between them gives the tank time to recover.
• Move the dishwasher and laundry to the evening. They pull from the same tank as the showers.
• Check the thermostat setting. Someone may have turned it down. We keep ours at 120 degrees, which the Department of Energy recommends.
• Look at the showerheads. An older high flow head empties a tank faster than a newer low flow one.

When it's time for a bigger one

If your tank is past 10 years old and running short, replacing it with one sized for the household you have now usually makes more sense than repairing the old one. Our replacement cost guide covers what goes into the price, and our water heater page covers everything we install and repair in Milford, Novi, and Farmington Hills.

Quick answers

Why does my hot water run out so fast?

The usual causes are sediment filling the bottom of the tank, a broken dip tube mixing cold water into the hot, a failed lower element on an electric unit, or a tank that's too small for how many people shower back to back. If it changed recently, it's likely one of the first three.

How do I know if my dip tube is broken?

Hot water that turns lukewarm quickly even though the tank is heating, plus small white or gray plastic bits in your faucet aerators or showerhead, are the classic signs. Replacing the dip tube is a repair, not a new water heater.

What size water heater do I need?

Size it by first hour rating, not just gallons. The first hour rating is on the yellow EnergyGuide label, and it should at least match the hot water your household uses in its busiest hour.

Countryside Plumbing is a licensed master plumber serving Milford, Novi, Farmington Hills, and southeast Michigan since 1979. Water heater repair and replacement is what we're known for, and we leave your house clean. Free quotes at 248-705-7543.