Hot and cold water flow

by Sue
(Bellingham, WA.)

We are on a well association of 45 homes. We had to turn our water off for 30 minutes the other day at the meter. No issues, but it was off for 30 minutes.

The next day, after this shut off, the water from all faucet outlets would run hot as desired, but then periodically have an 1-2 interval of cold water, then back to the desired hot water setting.

We can't figure out what is causing this. There is no air in the intermittent cold water....just the temp changes for 1-2 seconds. We have even tried just opening the hot side of the tap control so to make sure the cold wasn't mixing in some way.

Each time it is the same. You're running a bath, or washing your hands in the sink or doing dishes and you have on the hot water......at some point, cold water will then infiltrate and then right back to Hot.

We have a top of the line gas hot water heater....it is nine years old, but we just don't see the heater being the issue.

Do you think opening the relief valve on the top of the hot water tank for a few seconds could help?
We were thinking this because we had shut off the water the other day and maybe this is the cause some way or another of the intermittent cold water.

Any information you could share with us would be most appreciated.

Thanks so much,

Susan