Our TT has a filter installed but also We use a blue KDF filter on the end of the hose while filling our fresh water tank, the same type you would use on the city connection. We Also use tastepure in the tank, by CAMCO I think and available at Walmart. Lastly any water we use to drink or use to cook goes though a Pur pitcher type filter which sits on the counter. I am sure a Brita pitcher would also work. With three levels/types of filtering, we have never had bad tasting water.
2011 8314 BSS Rockwood Signature Ultralite
2005 Dodge Ram 2500 Quad-cab SLT