Originally Posted by RICKBETTY
I don't have the ability to blow out lines.
Actually, you do. All you need is a fitting for your municipal water intake, like this one from Amazon…
Then, use the compressor that comes with every Interstate, which you will find by opening the front passenger door and looking behind the plastic panel below the seat pedestal. It's pretty small, so it takes a while to build up pressure, but it will do the job if that's the only compressor you've got.
Not having an air tank to build up pressure, you will have to use the plumbing system itself as your air reservoir. First, gravity-drain the lines as much as possible by opening the low point drains and the kitchen and galley faucets. Also drain the water heater and bypass it. Then close the low point drains and faucets. Insert the blow-out fitting. Air up the system. Then open one faucet at a time (and flush the toilet to bleed water from that line as well), and close the faucet when water and air stop coming out. Repeat as often as needed until all you get coming out the faucets is air. Don't forget to hook up your exterior shower to blow out that fitting as well.
That will take care of everything except the water pump, which can't be blown out due to its check valve. For that you need to use RV antifreeze to displace the last vestiges of water.
I wouldn't recommend going to a service station to use their air lines. Commercial compressors tend to use oil as a lubricant and there can be oil in the air that you get from them. Doesn't harm tires, but not something I'd want in my fresh water system.