We have an under sink water filter. These things cost about fifty bucks for just the canister. You can't completely empty them. We use our moho for about 3-4 weeks out of the year. Cant we somehow use...
I use a cartridge filter in the fresh water line to the coach. It just sits in the bin next to the city water inlet. Connected with snap fittings so its is easy to insert in the line or remove and drain for storage. Wintertime, just remove it from line, drain and store till next year. Replace cartridge as needed.