If the surrounding parks charge higher rents and do not include water then you should be fine. Even if its comparable or slightly less, you should still be fine. MHP tenants tend to complain and threaten to leave but they never seem to actually leave, even the POH tenants. You can even send a list of the area rates and what they include with a phone number so they can verify for themselves. Of course most of them will never call. The list itself will cool them down. They have friends in these parks. They know they should be paying water. If area parks don't currently charge for water, they likely soon will.
As far as meters go, I would highly recommend hiring a service that installs the meters, reads them, and bills. I have sub-metered water in one of my parks and thats how I do it. Its a breeze. It costs me nothing. I just get the check every month. The company I use will install the meters for about the same price I can buy just the meter and they will read the meters and bill the tenants the maximum service charge. Thats their pay. I pay them nothing. They also handle off/on services if tenants don't pay. I'm not sure why anyone would do anything different. Let them choose the meters they want to install. I use http://universalutilities.com.
If you decide to go the flat fee route, be careful. Check your local and state laws. You may be able to use a Ratio Utility Billing System (RUB). Just be sure to do it fairly and treat everyone the same under the RUB rules you establish. One thing you never want to do is make money on water/sewer bill backs.
