The plumbing courses cover all the aspects that you will be required to deal with as a garbage disposal. You will be taught about the basic aspects as well as about health and safety issues and sanitation.
When you get to the house stand if front of the toilet and locate the water shut off valve. Should be down below the toilet on the wall. Just turn it off (righty-tighty) completely and flush the toilet. All the water should have left the tank, well at least most of it. If there is remaining water line repair get it out with paper towels or a rag. The important thing is that no more water came in. If it did then your valve is not shut all the way or not working and you need additional help.
Leaks can occur anywhere in your reverse osmosis water filter system. If this ever occurs, check the source of the leak. It may be from the hoses, fittings and the valves. Most of the time, some kind of tightening might be necessary. So make sure to securely tighten the fittings. If this does not work, you may need to replace the filter itself, however that might take a bit more work.
Sales representatives must know beforehand that almost all the answers above need to be encouraging. Otherwise, there is a slim to none chance a sale is made. Besides cold call prospecting, so much of the typical sales rep's time is spent trying to make sales when a sales situation does not truly exist.
Keep an eye on any leaks in and around the house. Inspect taps, pipes and your roof regularly. Watch for leaks and if you find them, get it water line repair as soon as possible.
People who own rental properties are great ones to give you information. With all of the service people needed for maintenance on their units, they typically know who to call and what level of work they perform. Most property owners will be more than happy to give you the information you seek. In fact, they were probably in your shoes at one time.
Re-coat the RV roof every two years. There are a several products for re-coating your RV's roof. Many will products recommend to re-coat every year, but it's not necessary, every two years is perfectly fine. A great affordable option is Camco RV Pro-Tec Rubber Roof Care System.