[mikey]

basically i need to stop screwing the top off the lid on the water tank in the van  and i need an attachment to the garden hose coming from the tanks in the garage

[Plankton]

Fit a ball cock. You'll need to drill a hole on the side of your tank apply some ptfe tape and screw it together.
http://www.diy.com/departments/delchem-side-entry-ball-cock-fill-valve/284491_BQ.prd
Then you need something like this:
http://www.diy.com/departments/jg-speedfit-flexible-tap-connector-dia15-mm-dia1/2-l300mm-pack-of-2/34377_BQ.prd
The threaded end will connect to the ball cock and on the pushfit end you might be able to fit your garden hose. If your garden hose doesn't fit you'll need to insert a small length of plastic or copper pipe into your hose to connect it.

[nathankaye]

No idea if this would work and depends on what hose your using to fill into your tank.
But again cutting a small hole in top of the tank and simply fitting a one way valve to it.  Connect your hose and away you go

[Smurf]

Do you want to save time transferring pure water into the van tank from the static tanks in your garage?
If so consider using a larger diameter transfer hose with a high lpm flow rated sub or inline transfer pump the less time it will take to fill. 

[mikey]

thanks i think i will keep unscrewing the lid  untill i find something else

[Stoots]

drill a hole in the lid the size of the hose bore

no it wont spill out when drving

[combat1]

Oh yes it will!

[Smurf]

Is it panto session already? 

[mikey]

i did think it would not leak but it did  and iam on my second lid  i thought  there would be some screw thread adapter to go on top of the lid so it would not leak but this i s proving difficult