How Long Will 40 Gallons of Water Last In an RV

An RV with 40 gallons of water

So, how long will 40 gallons of water last in your recreational vehicle when you’re boondocking, going off the grid? It is a question anyone planning to go dry camping without the perks of a camper park and its hoses needs to ask.

It will last as long as you make it last. Take a couple of long showers, wash dishes inefficiently, rinse your muddy shoes off and flush your toilet with it and it’ll be gone in a hurry. On the other hand, if you’re careful with the water, the 40 gallons will go a long way toward the next refill.

Those are the two simplified answers. In reality, there are many factors to add to the equation. You can start from the number of people you’re with to the season and the temperature affecting the consumption.

Why Save Water While Camping?

First of all, we should conserve water at all times, not just when we’re camping. Unfortunately, too often, we fail to realize how precious water is as a global resource. We may get a hint when we have to ration it. Second, when we’re camping in a beautiful place far from the nearest water tap, saving your drinkable water reserve will extend your visit.

The 40 gallons of potable water is roughly at the middle of what modern-day campers and trailers carry. A class B RV holds 20-40 gallons, class C between 35 and 60 and a class A anywhere from 75 to 100 gallons of water. Trailers, depending on their size, can store between 40 and 80 gallons in their tank.

But some of the water potable water on board can have a second life. There are two other tanks in an RV, for the so-called gray water and the black water. The gray water tank holds the used water that went through your shower and sink. You can’t drink it, but you can use it to wash some things and to flush the toilet. That water then goes into the sewage, stored in the blackwater or septic tank.

The water from the gray tank is clean enough for other jobs, as well. In a pinch, you can fill your windshield washer tank with it or clean dirty footwear or clothes. Every pint of the gray water you cleverly use will save a pint of potable water and delay your trip to the civilization.

Living in a camper parked far away from the first tap, you need to know where you can save the most water. Or, from the opposite angle, where you can easily waste too much.

Showering Makes the Biggest Difference

The shower is the topwater spender in a camper. A 2016 Water Research Foundation study says that Americans on average spend 15.8 gallons of water for a single shower. It typically lasts just under eight minutes and means that showerheads spray more than 2.1 gallons of water per minute. At that rate, you would be unable to complete your third shower with the 40 gallons in your RV before the water runs out.

So, a shower in a camper has to be different. Firstly, you can survive without a daily shower. Washing with a wet towel will have to do if you want your water to last. When you take a shower, turn the water on only until the part of you that you’ll wash next is wet. Apply shampoo and soap with the shower turned off, and rinse off the lather as quickly as possible.

And if you parked riverside, lakeside, or even on an ocean beach, you can wash the dirt off in any of them, then dab your face with a moist towel.

RV with 40 gallons of water

Be Stingy At the Faucet

In homes, faucets are tied in first place with the showers as water wasters. There’s no reason to think it’s different in a camper, so you’ll have to act differently. When you’re washing something in the sink, quickly wet it, turn the tap off and rinse quickly. If you have more stuff to clean, plug the sing and use the collected water. Don’t keep the water running while you brush your teeth or comb your hair. 

Toilet Flushes Water Away

Flushing the waste from the RV toilet sends a large amount of water into the black water tank. If possible, you can take some of the business outside, as well. And consider whether you need to flush everything.

The Equipment Matters

Facilities that come with the camper are often not optimized for efficiency, mainly to reduce the vehicle price tag. And sometimes the equipment is old and operating it can force you to waste too much water.

  • Fitting your RV bathroom with a low-flow showerhead will reduce water expenditure.
  • Consider installing water-efficient faucets for the same reason.
  • Low-flushing RV toilets are also available to reduce water wasting. 
  • Water pump 

A run-down, inefficient water pump may require fully open taps to build enough water pressure. As a result, it will probably deliver water in wasteful bursts. If possible, consider upgrading the pump and secure a steady, low flow of water.

Little Things That Add Up

  • When preparing meals, try cooking one-pot dishes. You will use less water both cooking and washing. Even better, eat sandwiches and wraps. If you just boiled something, say eggs, don’t throw that water away before you wash something in it.
  • If you bring paper plates, you won’t have to wash dishes after you eat. If you have the time, plan to buy biodegradable plates. You then won’t even have to either store the garbage or pollute the environment.
  • Pack wet wipes and sanitizer, too, to clean your hands and face without spending a drop of water. 
  • Dry shampoo will keep your hair clean, even if it doesn’t refresh you as splashing water on would. 
  • A half-liter (16.9 FL OZ) plastic bottle is an efficient gauge and rationing tool. In the morning, it will be enough for the teeth-brushing, face-washing – and coffee. Drinking out of it can help you keep track of your water intake. That’s important if you’re camping in a hot place.

In the End, It Is Simple Math

If you have time to prepare, you can test your water consumption before leaving for the trip. Fill the tank, and do the things you’ll do: shower, brush your teeth, cook a meal and wash the dishes. You don’t have to spend all the time in the camper – do the things you do that use water.

When you complete an entire cycle of daily things, measure how much you’ve spent. Divide the amount you spent with what you had at the start. The result is the number of days you’ll have before the water runs out. So, if you used five gallons for the daily chores, you’ll have eight days of water. 

Take into account that you’ll probably need to do something you forgot or use water for something unforeseen. Then, you can try to reduce the usage where ever it is possible and see how much the consumption will go down. Reduce it by a gallon, and you’ll be able to prolong your stay by two days. 

That is if you’ll be alone. If not, you can estimate. But be conservative, unless you’re sure your partner will be able to or even want to ration harshly in exchange for an extended stay in nature. If you’re confident, then divide the number of days by two. And that will leave an additional margin because not everything two people do will double the usage of water. Cooking, for instance, will barely increase it.

And after you have tried it in real life, you’ll see what other steps you can take to reduce your water consumption further. Perhaps change the showerhead, or even invest in that new pump. Saving water may quickly become your passion at all times – as it should be for everybody.

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