Fresh water tank access port

[AC0GV]

I would like to add an access port to my fresh water tanks. I have a 65 gallon tank in use for another project and wash it at least once per year with a bottle brush/mop and can see a difference. I recall a water proof port that people were adding to tanks years ago but cannot now find them. TNX

[daveandalice]

A lot of Casita trailer owners have installed them on their tank.

https://www.casitaforum.com/invboard...comment-155887

[LarryB.]

I recently installed a deck plate in my 2007 Casita. I bought a 6” Marine Boat Deck Round Access Hatch Cover on eBay and it provides more than adequate access into the 15 gallon fresh water tank.

I intended to follow Don Dayton’s installation process but I ran into a snag when I attempted to remove the bench seat. After I removed all screws holding the seat in place, I found that Casita had used rivets on the trim on the top of the seat next to the stove/sink cabinet and I hesitated to drill those rivets out; they were installed into the 1x2 attached to the inside of the stove/sink cabinet and the stove blocked access to the screws that were holding the 1x2 in place.

“Plan B” was to reinstall the screws that I removed and, from the Casita's external access door, to simply spread the pipe strapping on the side of the tank that holds it in place. Also, rather than using a drill and jig saw to cut out the opening, I just used a utility knife to cut out the opening in the top of the tank.

Unlike the comments in the Casita Forum page, I did not install any type of backing under the deck plate inside the tank. Using silicone caulk, stainless steel bolts, flat washers, and self locking nuts, I fastened the deck plate to the top of the tank. Also, to insure that the pipe strapping did not slip, I applied a generous wad of silicone caulk at the edge of the tank on/under the bend of each of the pipe straps (left side of pictures below).

The 6” deck plate gives me more than enough space to use my shop vac to remove any water that remains after draining the tank followed by an old bath towel to mop up any residue.