30 gallon is standard in most of our campers if you have a shower but you have a choice or 30, 16 or 10 gallon tanks. In a camper with sink only, 10 gallon tanks are adequate. Remember that for every gallon of water you store in the tank, you are adding 8 lbs. of weight to your camper. If you don’t need a shower in your camper, we have a new sink option in 2019, a hand-pump sink. With a hand-pump sink you will get our standard stainless-steel sink basin and a hand-pump faucet tied to a feeder hose that runs down into the cabinet below. You may feed the tube into any liquid source to pump through your sink faucet. Read all about it here in the FAQ section, just click on “most popular new option for 2019: Hand-Pump Sink).