How to Install an Outside Grey Waster Tap 1 Comment


Fit an outside grey waste tap to your motorhome.

On many motorhomes including our Hymer B590 and also on our previous van, the grey water release tap is located inside the garage. The downside to this arrangement is that every time you want to empty the grey water tank you have to unlock the rear door and release the tap.  This can end up as being a bit of a chore.

When we were away in 2015 I got a little sick of the situation and decided to install an outside tap to remedy the situation. You can purchase a proper motorhome one from an accessory shop but the price is high and they tend to be quite big and bulky neither of which appealed to me. My solution came from visiting a DIY (Bricoman) store when we were in Spain. I purchased a tap that was meant to be installed on the water main, cost was around €6 or €7 and all I then needed was 2 screws and some silicone sealant.

I measured the inside diameter of the waste pipe located on the outside of the van and made sure that one end of the tap would fit inside, It was just a tiny bit big but as it’s made of brass I filled the edges slightly  so it would fit inside (very easy).

I placed the tap end inside the waste pipe and then drilled two small holes through the waste pipe and then through the tap itself so that I could use 2 screws to keep the tap solidly in place.

I then simply sanded the inside of the end of the waste pipe a little and applied some silicone sealant around the edge of the tap section that goes inside, (sanding the plastic helps the silicone sealant to stick better) Insert the tap and simply tighten the two small screws to keep the tap in place, wipe of any excess sealant off and your finished.

Once installed just leave your original inside tap in the open position and use your new outside one instead.

NOTE: If the temperature drops to near freezing then any water in the plastic pipe could freeze and maybe split the waste pipe. This would also affect any type of outside tap hence the original tap being located inside the van. The solution is simple though, just leave the new tap in the open position and used your original inside tap as before.

Motorhome Grey Waster Tap: Pro’s.

Well it’s cheap and easy to fit.

There is no maintenance.

It works perfectly in all weather and never leaks.

It’s very compact.

The handle is also the same as most fresh water taps you typically fill your van from so if you come across one with no handle you could borrow your very own handle.

Saves you open you rear door every time you want to empty your grey water tank.

Motorhome Grey Waster Tap: Con’s

Well it’s probably a tiny bit heavier than a “proper” plastic tap.

Total cost is about €8, not having to keep opening the bloody garage door, priceless.


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