Waste tank tap size

25 mm hose is 1 inch and I read that you get av3/4 inch tap for it. This doesn’t seem right to me?

Shenn wrote:25 mm hose is 1 inch and I read that you get av3/4 inch tap for it. This doesn’t seem right to me?

I had a lot of trouble with my waste pipe and tap and replaced them and feel sure that there was a plastic 'reducer'.  There are also a couple of variations of the pipe's actually ID and I found that the best and most secure fitting was the pipe supplied by Auto Sleeper spares rather than the standard caravan one.

This is a screenshot of the AS Parts catalogue 2023 Page 9[You must be registered and logged in to see this link.]

The blue and grey pipe at the bottom is listed as 28mm. That size is the semi rigid pipe used on caravans. The actual size of those pipes shown is 26mm internal diameter. Many suggestions say that garden centres sell black pipe for garden water features that is correct size, it's not, it's 25mm/1" and will not go on the spigot (maybe it will if immersed in hot water first). If ordering from AS , always worth getting enough for two applications,  firstly due to minimum postage and secondly because you will need it in the future.

Paulmold wrote:The blue and grey pipe at the bottom is listed as 28mm. That size is the semi rigid pipe used on caravans. The actual size of those pipes shown is 26mm internal diameter. Many suggestions say that garden centres sell black pipe for garden water features that is correct size, it's not, it's 25mm/1" and will not go on the spigot (maybe it will if immersed in hot water first). If ordering from AS , always worth getting enough for two applications,  firstly due to minimum postage and secondly because you will need it in the future.

I know it sounds odd but when I went to change my waste pipe for the caravan type I found that the internal diameter was a tad larger but the AS supplied stuff fitted perfectly.  Bill.

So I need the 28mm tap and the 28mm hose?

Shenn wrote:So I need the 28mm tap and the 28mm hose?

Look at the post above.  I think that you will need one of the plastic reducers.

I measured the spigot on the fresh water tank and it is about 20mm diameter 6cm circumference 

I measured the hose attached to the waste  tank and it was about 20.69 mm and 8.5 cm circumference

So 28 mm hoses and taps are going to be too big? What about 25 mm hoses and taps?

I can only find 25mm or 28mm online.

Do you have a photo of said spigot, whereabouts on the tank is it fitted?

If you only have a 20mm spigot a 25 or 28mm hose will obviously fit on it but you will never be able to stop it from falling off, think condom. 

I will get a photo tomorrow but it is a couple of inches long plastic and sticks out bottom of tank. 

That is what I was thinking although condoms didn’t spring to kind!

Spigot
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Hi Shenn
I've just had a quick look on ebay.  You can get PVC tube of the sort of size you are looking for smooth or corrugated(search for 20mm hose), sold for garden pond systems.  The great thing about thermoplastic tube is that if it is slightly too small for the spigot you can heat the end of the tube up in a cup of just off boiling water which will soften it sufficiently for you to be able to push it over the spigot.

Hope this helps!

Thanks Nick very helpful