Home Improvement Stack Exchange is a question and answer site for contractors and serious DIYers. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

The building just installed some new pipes and since then I believe that the hot showers cannot last as long as they once did.

Is there a sub-optimal way to hook up a new cold water intake that would mean that cold water would mix prematurely with the hot water running to the bath or anything that might cause a lowering of the available hot water?

share|improve this question
possible duplicate of Did the plumber hook up my water heater backwards? – longneck Jan 17 '14 at 15:39
Installing a smaller tank, or hooking it up backwards. – Tester101 Jan 17 '14 at 15:40
@longneck This is not a dup because the OP's asking specifically about cold water mixing. – Edwin Jan 17 '14 at 19:22
@Edwin: Reversed connections would result in cold water which is added to the top of the tank making its way to the bottom before the heater has adequately heated it. – supercat Oct 18 '14 at 13:38

There is a way that cold water would mix prematurely with the hot water. This could happen if there is something wrong with the cold water dip tube. The cold water dip tube takes the cold water from the connection at the top of the tank to the bottom of the tank where it is heated. If the dip tube becomes faulty or is removed, the hot water from the tap will run out quickly.

Failure of dip tubes is common, especially with water heaters from the mid 90's. There is also the outside unlikely chance that it was removed when replacing the pipes.

Of course, you get the same effect if the hot and cold connections are reversed.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.