Well, first off, not looking hard enough, cause you quit before you found em, LOL
Tank (and WATER PUMP) usually very close to wherever you connect city-water hose. I AM assuming CONQUEST TRAILER vs CLASS-C? Some floor plans put the tank/ pump, drains under BED? LOW POINT DRAINS on GS are often a BLACK T-HANDLE, pull up to open drain, should be x3 (Hot, Cold, and FW Tank); also LEARN HOW TO PROPERLY WINTERIZE NOW AND DE-WINTERIZE AND SANITIZE come SPRING? You may have green ALGAE growing now, potential to clog pump, strainer (if equipped) and make one sick if drinking, but proper sanitizing can CURE all that. TIP: TAKE PICTURES OF ANYTHING YOU QUESTION. GOOD LUCK