Yes, the two colored lines are low point drains to drain the water out of all the lines in the camper. You want to find the drain for just the water tank. It is not something that is standard in campers,it can be different types and locations. First,look at all the stickers on the side of the camper. Does one say fresh water drain? If so look all around that area,most likely under the trailer for a small valve or cap. If you find nothing marked on the out side then you need to locate your fresh water tank. It can be inside sitting on the floor in a cabinet or under the dinette or sofa or hanging under the camper.Now is there a small valve on or near the tank? This is it. If there is no valve there is there a small hose going out through the floor(on inside tank model) the valve may be at the end of the hose under the trailer? Most drain painfully slow as it is just a small hose or valve. Hope this helps.