bad tasting water!

That’s just weird!
Just drink from the tank tap ?

Pure water has no taste, so maybe the unfiltered water from the tank has something in it that makes it taste better to you however your filter is removing that “taste” you like from mains water.

Eric
You mean "plumbed" to the sink it seems. Perhaps the tap sealing washer in the SUS system is degrading and tainting the taste. It might be easier to replace the sealing washer with an inert one to see. Always do the easy first. You seem to have done the hard stuff first.
Not a good idea to fill any vessel you drink from by using a garden hose. If sitting in the sun and not a FOOD grade hose, the plastic hose emits carcinogenic particles into the water, which goes into your drinking tank. Just not wise. Vets say that is the cause of many dogs having cancers by filling water bowls from garden hoses left in the sun to degrade.

I think it could be the tap! I once fitted an eBay tap (Chinese?) to out bathroom in the house. The water from that tap tasted bad until I replaced it with a locally-made tap.

There could be a small critter got into the line at some stage and is stuck at the tap (small frog, caterpillar from wasp) I have seen this before. The other thing you said was you have replaced the water hose 3 times. Was the hose from the same batch or purchased at different times or different supplier, as I have come across a bad batch of hose before and it made to water undrinkable.

If the tap is connected with braded lines , sometimes the bad taste is from those, even brand new ones can have a taste. If you van has been sitting for a while, run the tap for 5 to 10 seconds sometimes clears this up.

Another thought
If you run the tap for a fair period of time , I would think wherever the bad taste is coming from would become far less, the taste should at least get better.
A bad washer or dead stuck bug or whatever couldn’t keep contaminating the water to that extent.
Hope you can find what’s going on , it’d be bloody frustrating!

Try emptying the tank you fill with the green garden hose, use the food grade one, flush a bit and try the water see if it tastes bad like you're other tank to eliminate the food grade hose not adding that yummy chemical taste you may be use to from the garden hose. I put some lemon juice in a new tank once went for a drive so it mixed in let it sit for a day or 2 and flushed it out all good.

Have you tried this

https://abigpeacheyadventure.com.au/clean-caravan-water-tank/


Cheers
Gazz

When you change your tap, before connecting it permanently try running some water through and tasting it. Just might be the poly pipe for some odd reason.
Also check the 12v pump ....... something may be amiss there.
Good luck !

Cheers
Jim

What happens if you taste the water straight out of the tank, not running it through the hose and tap?
Just gravity feed out of the spigot on the tank into a cup or jug.

G'day Eric, I learned during my years working on building sites NEVER to drink water which has run through a garden hose. Not for the taste but for the fact that bugs grow in wet environments which can lead to illness. There are purifying tablets you can buy for your tanks.

Eric, have you tried someone elses food grade hose and see if it is still the same. The fact that a hose is food grade does not guarantee that it will not taint the water. All that you can guarantee with food grade hoses is that they will not introduce the same carcinogenics into the water that Vinyl hoses do.

I have not heard of this happening lately. However, some years back this was a problem. Bunnings were supplying food grade hoses that tainted the water. Using hoses from a different manufacturer cured the tainting problem

I suggest you try some different hoses. Perhaps you could use your garden hose. If you just use it for testing you should not get too much in the way of carcinogenic products (many of us used common garden hoses before the food grade hose came on the market and we are still alive.)