2003 190V Water system
Kitchen cabinet with hot water tank seen on right and water pump on left. You can see the red handle on the tank selector valve, here turned to use the outside tank. I rotate it 90 degrees clockwise to select the inside tank.
Some observations of this arrangement
When I am using the pump, it will draw water from either the inside tank or the outside tank, depending on the position of the tank selector valve. It will not draw water from both tanks at the same time. I usually use up the inside tank first, then manually switch over to the outside tank after the inside tank is empty (using the large red-handled tank selector valve located inside the kitchen cabinet next to the fridge).
Please note that many if not most Roadtreks have a water line connecting the inside tank (under the rear passenger-side dinette couch on mine) with the outside tank (mounted under the van). If you open the valve on this connector line, the water from the inside tank will gradually drain via gravity into the outside tank as you use the outside tank up. My particular Roadtrek does not have this connector line. There was a brief period during which they did not install them.
How to Fill Your Water Tanks
Hook your hose up to the city water connection then open your tank fill valve (the red or yellow valve near the city water connection), the tank selector valve (located inside next to the water pump) will determine which tank receives the water. If I want to fill both tanks, I must manually switch the valve over to the other tank once the first tank is filled. How do you know when a tank is full? Water will start coming out of the outside fill spout (assuming you have the orange plug removed from the spout, if you don't have the orange plug removed, it will shoot out from the water pressure :-). Alternatively, you can use a hose to fill each tank through its outside fill spout, which I find to be more work.
I also noticed that there is no inside shutoff valve on the tank fill line, to close off this line in the winter. Whenever there is water in the inside tank and the tank selector valve is set to use the inside tank (as it would be for winter use), there will be water going all the way down to the tank fill valve which is located outside. This water will freeze. I would probably add a shutoff valve on this tank fill line near the water pump to prevent this if I ever want to camp in freezing weather.
City water hook-up. The red valve is my tank fill valve (here shown in the off position). You can also see my outside shower faucet where you can hook up a shower hose.
How to Drain the Water Tanks
To drain the front outside tank, simple reach underneath the tank and unscrew the small cap that covers the drain outlet. Don't forget to screw the cap back on once the tank is empty. Knock on wood, I've haven't lost my cap yet.
To drain the inside rear tank, first select the inside tank with the tank selector valve (the one with the big red handle located near the pump). This allows water from the inside tank to travel to the tank fill valve. With the pump OFF, now open the tank fill valve. This will allow the water from the inside tank to travel all the way to the outside shower cold water faucet. Open this faucet and it will drain the inside tank!
How to Drain the Hot Water Tank
Make sure your hot water heater is turned off. The water faucet for the outside shower is one of the lowest points in the water system. With the pump OFF, opening both the hot and cold outside shower faucets will slowly drain the hot water tank. To facilitate draining the hot water tank, also open the hot water faucet at the sink to let air into the tank as it drains.
How I Winterize My Roadtrek
I've been using an air compressor to blow out my water lines for the 16 years that I've owned our Roadtrek and I've never had any problems with freezing. First I will empty my water tanks (including hot water tank) as described above and also empty my black and graywater tanks. I set up my air compressor to provide 40 psi of pressure and hook it up to a hose (which I blow out to make sure it's empty of water) and then hook the hose up to the city water connector.
Now I will proceed to open each hot or cold water faucet in succession, letting the air blow the residual water out of the lines. I start with the kitchen sink and will alternate between the hot and cold water positions until only air is coming out. Depending on your air compressor, you may need close the faucet to let it build pressure back up before opening the faucet again. Keep repeating until only air comes out from both the cold and hot water positions. Then I do the shower head in a similar manner (which I hold over the kitchen sink to collect any water that spritzes out). Next I'll open the water foot valve on the toilet to blow that cold water line out. It's ok if you get a little water in the toilet and dump that into the black water tank. You'll be dumping some antifreeze solution into the blackwater tank anyway. I will then go outside and let air blow out the hot and cold lines on the outside shower hookup.
Once all the lines are blown out, I will drain the gray water tank again to try to get out any water that may have entered from the sink during the blow-out process. Now make sure both gray and blackwater drain valves are closed. I next use a gallon jug of the pink Propylene Glycol-based antifreeze solution designed for RV drinking water systems. I will pour about 1/3 of it into the kitchen sink drain (this will protect the sink trap as well as the graywater tank), 1/3 into the shower drain on the floor of the Roadtrek, and 1/3 into the blackwater tank via the toilet to protect the blackwater tank. Wipe up any residual antifreeze solution inside the toilet and on the toilet flapper valve because it becomes sticky when it dries and it could "glue" your flapper valve shut as it sits over winter (wonder how I know this :-).
The last step you need to take is to remove the clear plastic filter that sits on your water pump intake. This will let any residual water drain from the pump and the filter usually has a little water in it that needs to be dumped out (because it will freeze and crack the filter if you don't - again, wonder how I know this :-). I just leave this filter off all winter, but remember to re-install it next year before you fill your water tanks.
Make sure all your water hoses and filter cartridges are blown out and remove anything from the RV that might freeze. The last thing I do is to open the tank fill valve, then stick a small plastic dowel (about 1/4" diameter - or anything similar you can find) up into the one-way valve at the city water inlet, this lets that last little bit of water drain out that was sitting just above the one-way valve.
How I Sanitize My Water System
Since you will be drinking and cooking with your fresh water, it should be kept free of microbial contaminants. If I have not used the Roadtrek water system for more than a week or two, I will perform the following sanitization using household bleach (5.25% sodium hypochlorite). I take 1/2 cup of bleach and dilute it up to a half gallon using a 1/2 gallon water pitcher. This makes it a little safer to deal with. Also make sure the household bleach you use is fresh. It has an effective shelf life of only 6 months.
Empty the inside and outside water tanks and water heater as described above (make sure your water heater and water pump are turned OFF). Then add a few gallons of water to each water tank using a hose at the outside fill spouts. Do not connect up a hose to your city water connection, since that will fill your water heater with non-chlorinated water. Now pour half of the 1/2 gallon pitcher of bleach solution into each of the water tanks using the outside fill spouts. (In other words, each tank ends up getting about 1/4 cup of household bleach.) You may find that a curved funnel makes this job much easier. Now fill up both water tanks completely using the outside fill spouts. Filling the tanks will mix the chlorine solution with the water.
Next, turn on your water pump. You will hear the water heater tank filling as the chlorinated water gets pumped into it. You can open the hot water faucet at the sink to relieve any air pressure in the hot water tank. Once the chlorinated water starts coming out of the hot water faucet, shut it. Now I switch over the water tank selector valve to the other tank (doesn't matter which tank you start out with) and I pump water briefly through the cold water faucet at the sink, then through both the hot and cold shower faucets. I'll also pump a little of the chlorinated water through the outside shower faucets and the toilet flush line. This loads the entire plumbing system with chlorinated water. Now top off both your water tanks using the outside fill spouts so that they are completely full.
Next you wait for the chlorine to do it's job. This should be a minimum of 3 hours. I like to let it sit overnight. Once the tanks are sanitized, then drain both water tanks and the water heater and refill with fresh water. You can use the city water connection for filling this time if you want. Some people will drain and fill the tanks a second time to completely get rid of any chlorine taste. I don't bother. The chlorine is completely safe and we use a filter on our kitchen faucet that eliminates the chlorine taste from any water we drink.