I know that the water lines in the coach are tested to 100 psi, but the safe operating pressure is 65 psi. IMHO everyone should carry a good regulator because some parks have water pressures over 100 psi. I have a Watts adjustable regulator and a 2 stage filter both of which I bought here
http://www.rvwaterfilterstore.com/index.htm This site has a lot of info on water systems. I use their most popular dual canister system. This has a 1 micron sediment filter followed by a 1/2 micron carbon filter. 1/2 micron is small enough to filter out most water born micro-organisms. Everything has a flow rate of 4 gpm at 60 psi. This gives good showers and the water taste great! The filters typically last over 6 months. The whole system cost is only a little over $100. I think this is little to pay to have good safe water where ever we travel. Many RV parks have well water and we have no way of knowing the quality. Since most organisms will enter the body via the eyes and mouth while showering it's important to have the whole system have safe water.