Q: Why is my city water connection filling up freshwater tank?

Most responses are: Replace the water pump.

I am in favor of debugging before throwing money at things.

Do the following steps:

1. Turn off city water, turn on water pump, open faucet, turn off faucet, turn off pump, open faucet to depressurize, close faucet.
2. Try those steps 3 or 4 times with city water turned off.
3. In most cases, the check valve will reset itself on the water pump.
4. When done 3 or 4 times, drain freshwater tank down some, turn on city water and see if it stills fills up, quite often it will be fine and then you had to replace nothing.
5. If the check valve has truly gone bad, you can try to replace just it, or replace the water pump.

Feel free to reach out if any of this is confusing.

Joe, jtesta@teci-rv.com, 740-206-8522.