Hade a code for the evap valve stuck closed. Got unbelievable the car checking it and found the canister about half filled with water. I don't understand how water could get in it. Input welcomed.

 

Water or gasoline? You can fill that canister with gasoline if you always keep clicking on the fuel nozzle at the gas station.

 

I thought it was gas to at first but then I smelled it and it was water. I'm 100 % sure it's water.

 

If it's water, it can possibly be from rusted canister part, issue with evap vent hose, or issue with 3-way joint or the evap drain joint.

2003 Accord 4 cylinders had an issue where moisture can enter at the evap canister drain joint. The 2007 Accord 4 cylinders should already have an updated drain joint.

Examine the evap canister, the evap canister vent shut valve, and the evap vent hose all the way to the drain joint. Both 4 and 6 cylinders had similar EVAP canister parts.

Honda TSB 03-040