Cumminalong wrote:
Wanting to extend the water drain outlet so it reaches the edgeof the tank, like to put a tap on it.what can I use? John
Assuming it won't spend a lot of time in the direct sun, you can purchase some inexpensive flexible plastic line (not PEX) and a 1/4 turn sink/toilet shut off valve. clamp the line to your current valve and leave it open, controlling the drain from your newly and more conveniently mounted shut off.
This type of valve was installed by the manufacture on our 13 year-old mini travel trailer we use for overnight hops. They still work fine on the fresh water tank and off the PEX low-point drains.