water system question

[Alex]

On my ' 72 29 foot Ambassador, I have a water filter cartridge (the blue canister) and a water pump filter metal screen in a plastic canister) assembly under the sink. What is the difference/purpose for these two assemblies?
Also, does anyone know where I can obtain the small V-belt for the water pump assembly? Is it easy or hard to replace?
Mine still works, but does not look like it will last long.
Thanks
Alex

[ke4pk]

The screen is to filter out sand or large impurities which may damage your pump and should be located between the fresh water tank and the pump. The water filter is to improve the taste between the water supply and the faucet.