I have a 2 unit rental home. The downstairs complains that the water takes a long time to heat up. In addition, they shared that about 5-10 min. after the shower has been turned off, there is a gush of water that comes from the pipes as if the pipes are clearing out.
The upstairs unit complains of the same thing and also says that when they have hot water, it will get cold very quickly even though there are only 2 people living in the house.

3 problems, 2 heaters?

1. Gas/electric Water heater? If Gas, then there is crud on the bottom of the tank. The drain valve should be briefly opened monthly until it runs clear. I do it yearly.

2. The diverter is sticking. The diverter is the knob you pull on the spout to change the tub water to the shower head. The water in the pipe from the diverter to the shower head is emptying into the tub.

3. Broken dip tube.

See: HowStuffWorks "How Water Heaters Work"

Thank you.
1. There is one heater for both upstairs and downstairs (4 bathrooms-4 showers). The heater is electric. It appears that no matter which shower, the same problem occurs.

2. Where is the dip tube? On the faucet itself?

3. Do you have a solution to the water gushing 5-10 minutes after the shower is turned off?

4. Also, this is a new problem. The old tenant did not report this as a problem.

... also, any (any) plumbing work done on the house recently ? Do you have hot water circulating pump installed ?

The most recent plumbing work was the installation of 2 low flush toilets in the past 6 months. No hot water circulating pump has been installed. Do you recommend that?

(2) Dip tube is on the water heater. See the "How stuff works" link.

(3) Manually move the diverter after finishing a shower. Replace the tub spout/diverter assy or live with it.

Dianecho: Hot water circulating system is designed to solve hot water delivery problem. You can install retrofit pump that doesn't require wall cutting. Pump installs on the water heater while a special thermo-check-valve is installed on the most remote plumbing fixture.

I agree with Milo that if you install a hot water recirculating pump will solve your problem, I have installed a few of the Watts pumps see the attached pdf, good luck.

John