Camping off the grid in remote locations, commonly known as boondocking, has been our favorite way to RV for more than 20 years. But the longer you want to stay in one place, the more you need to pay attention to your RV’s gray tank to avoid filling it up too fast. Over the years, we’ve learned many ways to conserve water, allowing us to stay in our favorite camping spots for weeks instead of days. In this post, we share 16 of our best tips for saving gray water tank space when you’re off the grid.
16 Tips to Save RV Grey Water Tank Space
When you’re out boondocking for an extended period, one thing you need to be mindful of is conserving space in your RV’s gray water tank (or grey water tank, depending on the country you’re in). Nobody wants to break camp early just to dump it.
Over the years, we’ve gotten really good at conserving water, power, and space in our holding tanks, enabling us to extend our stays as long as possible. However, during our first 20 years of RVing, we were in a Class A motorhome, which gave us more room in our tanks compared to smaller rigs.
For RVers with smaller holding tanks (including our new Outdoors RV 19MKS travel trailer), we’ve compiled this list of tips to help keep your RV’s gray tank from filling up too quickly. So, here are our best bathroom, kitchen, and general gray water tank conservation tips.
NEWBIE NOTE: Most RVers know that the water from sinks and the (indoor) shower flows into the gray tank. For more info on the topic, check out our post “What is gray water?” And, of course, working to save RV gray water tank space also conserves fresh water. So even if your rig has a large ratio of gray-to-fresh-tank capacity (a large gray tank in relation to the fresh tank), these tips will help extend your stay.
Bathroom
Here are six ways to conserve space in your RV’s gray tank while boondocking. Even if you don’t use them all, you’ll appreciate the extra camping time when you try even a few of these tips:
A Navy shower is a water-saving technique originally used by sailors to conserve fresh water aboard ships (hence the name). To take a Navy shower, you get wet, turn off the water and soap up, then turn the water back on to rinse off, using as little water as possible.
Taking a Navy shower (where you wet yourself, then turn the water off while you soap up) is a great way to conserve both fresh AND gray water.
We’ve gotten so good at taking Navy showers that we can each take a thorough shower in just a gallon or two of water. Of course, we’ve had help from a really good water-saving showerhead (see below).
Use Cleansing Wipes
While we shower every day, not everyone finds that necessary, especially when trying to conserve fresh water and the space in their gray tank. On days when you don’t get too dirty or sweaty (and you’re okay skipping a regular shower), cleansing wipes come in handy as a way to wash up without using any water at all.
- Member's Mark Adult Washcloths (240 Count)
- Product type: ABIS_BOOK
Use a Water-Saving Shower Head
You can also save space in your RV’s gray tank by using a water-conserving showerhead with a shut-off valve. This lets you take a satisfying shower using a smaller volume of water, control the water flow, and easily turn the water off when you’re soaping up or washing your hair (as noted in the “Navy shower” tip above).
You may have read our post about the best RV showerheads. These are popular with RVers for providing the feeling of a strong spray while still conserving water. There are several different types, but this is the excellent (and inexpensive) model we’ve been using for years. We love it for the satisfyingly firm spray, combined with very low water flow, AND the ability to control that flow.
- LIFETIME LIMITED WARRANTY: You can install with confidence, knowing this Delta shower head is backed by Delta Faucet's Lifetime Limited Warranty
- INTENSELY POWERFUL: Immerse yourself in the steady, intensely powerful full body spray with forceful streams of water to satisfy all of your showering...
Capture Shower Water While Bringing It Up to Temperature
When you’re about to start your shower and run the water to bring it to your desired temperature, don’t let it run down the drain! If you do, it will contribute to filling the gray tank sooner than necessary and will also reduce your supply of fresh water. That run-up water can be repurposed for other uses, preventing it from taking up valuable space/capacity in the gray tank.
We’ve always kept a 1-gallon plastic pitcher in our bathroom to collect that “run-up-to-temp” water, which we then use to flush the toilet. You could also use the water to wash dishes or anything else you might need water for.
- Capacity: 1 Gallon
- Three-position lid that turns for free pouring, pouring with ice guard or closed
Shower Outdoors
To prevent adding water to your RV gray tank, you can use your outdoor shower, provided it’s allowed where you’re camping (and assuming your RV has an outdoor shower). As always, make sure to use environmentally friendly, biodegradable soap.
- RICH LATHER, CLEAN FEEL: Dr. Bronner’s Pure-Castile Magic Liquid Soap is a true soap, with rich, thick lather that feels great on skin, rinses...
- MADE WITH ORGANIC OILS & CERTIFIED FAIR TRADE INGREDIENTS: Dr. Bronner's Pure-Castile Magic Soap are made with over 70% certified organic & fair trade...
Besides being biodegradable, we love Dr. Bronner’s for another reason — it lathers well but rinses off easily. That means less water is needed to rinse when showering, saving even more fresh water and grey tank capacity.
Where allowed, using your RV’s outdoor shower is a great way to keep too much from filling up your RV’s gray tank!
You can learn more about outdoor showers in our posts, “Is an RV Outdoor Shower Worth Having?, and “Components of a DIY RV Outdoor Shower Kit.”
Use an Astringent or Facial Cleanser
One very easy way to conserve the amount of water that flows into your gray tank is to use an astringent like witch hazel or a commercial facial cleanser instead of washing your face in the morning and/or evening.
Since our routine includes showering at night, we use the following type of facial cleanser on a round cotton pad each morning, adding zero water to the grey tank in the process.
- Dual-sided, one surface for exfoliation, one for more gentle use
- Use the raised, textured surface to gently scrub and exfoliate the face
Use a Dry Shampoo
You can also use a dry shampoo on some days to save water, especially if you have longer, thicker hair (Peter does have an unfair water-saving advantage here). 😂
- Spray generously on roots and throughout hair
- Let product sit for 30-60 seconds
Kitchen
The following are five kitchen-related ways to help keep your gray water tank from filling up too fast:
Use Paper Plates & Cups
We generally try to avoid disposable single-use items, such as paper plates; however, we do trade some paper usage for water savings when we’re on extended boondocking trips. Using paper plates and cups when you’re boondocking means less dishwashing, saving both fresh water and gray tank capacity.
Paper plates and cups are an easy way to save water… AND make cleaning up after meals faster, too!
PRO TIP: Buy plates and cups that are all paper (no plastic), so you can use them to start your campfire, saving on water, gray tank space, and accumulation of trash.
Use a Catch Basin to Collect Dishwater
Use a catch basin (like a dishpan) to collect dishwater and toss it outside. Just be aware that this is not a tip that can be used everywhere, as some places prohibit the practice because food particles in the dirty dish water can attract animals to your campsite. For more info, see our post “Can You Dump RV Gray Water On the Ground Legally?” Either way, we always use and recommend environmentally friendly biodegradable products.
- This liquid Dish Soap cuts through grease, while making dishes clean and bright
- Our Dish Soap contains cleaning agents and other thoughtfully chosen ingredients to make grease disappear
Pre-Clean Dishware, Pots & Pans With Napkin
Using a paper napkin or paper towel to wipe excess food out of pots and pans (and off of regular plates if you use them) before washing is a good conservation tip for boondockers. Not only will you use less water and save gray tank space, but you’ll also be removing the food particles (as noted in the previous tip) so that if you’re disposing of dishwater outside, you’ll be reducing food odors that can attract wildlife.
Wash Dishes With A Spray Bottle
Many campers, especially those who tent camp or have smaller rigs with smaller fresh and gray water tanks, prefer to wash dishes using a spray bottle containing a mixture of water and white vinegar. You can pre-wipe any dishes with a napkin or paper towel (as mentioned above), spray them with the cleaning solution, and then wipe them off with another paper towel, cleaning the dish or pan completely with virtually no water use.
Pre-mixing a dishwashing spray, and then using it in place of a lot of water, can really cut down the amount of water going down the drain.
Cook Meals on a Grill or Griddle or Using a Single Pot
Plan meals that you can grill, or cook on a camping griddle. You can also make one-pot meals or use a pie iron. All of these tips minimize the number of pots, pans, and utensils that need washing, thereby saving both fresh water and gray tank capacity.
General Water Saving Tips
Finally, here are four additional ways to conserve space in your RV’s gray water tank while boondocking:
Start Your Trip With a Completely Empty Tank
This should go without saying, but be sure to fully empty your gray tank (and black tank) before heading out to your boondocking spot, leaving the maximum amount of space possible. This will start you off on the right foot as you seek to conserve space in your holding tanks.
Emptying out your RV’s waste tanks before heading to a remote spot ensures you can maximize the length of your stay.
Install Low-Flow Aerators
You can install low-flow aerators in your faucets to reduce water use, which also means not filling up your RV gray tank as quickly. Different types, brands, and models are available and should work well for most RV faucets.
- 【NOTE: Measure Dimension before Buying】 Aerator Dimensions: 21x21x12.2mm 0.83x0.83x0.48 Inch, please measure your original aerator dimension...
- 【Smooth Flowing Faucet Aerator】1.5 gpm max at 60 psi (5.7L/min)
Don’t Run Faucets Unnecessarily
This is something we should all be doing, regardless of whether we’re camping or not. Once you establish this habit as a boondocker attempting to conserve tank space and fresh water, you’ll find that even when you have an endless supply of water available (like when you’re back at home), you’ll be more likely to avoid running your faucets unnecessarily.
Some examples of this include washing dishes, brushing your teeth, or washing your hands. Every drop that runs down your drain fills your gray water tank with more water and reduces the amount of water in your freshwater tank.
Use a Blue Boy
A “Blue Boy” is a portable waste tank that some RVers carry to empty their gray (and/or black) tanks into. You can read the details about these totes in our post “3 Best Portable RV Dump Tanks (or Blue Boys).”
Just remember that you’ll need to have the space and weight capacity to carry a Blue Boy on your rig and a way to get it to a dump station once it’s full. Water weighs in at more than 8 pounds per gallon. Calculate accordingly to make sure you’ll be able to handle a full tank and that you can safely add that amount of weight to your RV.
- Simplify RV Waste Disposal: Make waste disposal hassle-free with Camco's portable waste tank. Easily transport waste from your RV black water tank to...
- Effortless Transport: Haul your waste with ease with no-flat wheels built for any terrain, an oversized handle for easy maneuvering, & a steel tow...
Using some of all of these ideas should help you extend your boondocking trips pretty substantially. If you have any additional tips that you use to preserve the space in your RV’s gray tank, please share them in the comments below.
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Marc Goldstone
Wednesday 4th of June 2025
I solved the grey water problem in three ways: 1) Plumbed RO waste water back into the fresh tank while boondocking. 2) Added a tiny 12VDC hot water recirculation water pump enabled for 2 minutes after turning on the shower light. When the pump is running the hot water is pressurized a couple of PSI higher than the cold water so hot water flows through the opened shower valves and back into the cold-water pipe. When pump turns off step into the shower and open the shower head's valve and you get instant on hot water with no water waste. 3) Added a macerator to the dump valve and a return pipe that can recirculate the pulverized waste back into the black tank. By closing the black and opening the gray gate valves the macerator pump takes gray water and pumps it into the black tank. Doing this lowers the gray tank level which works well as the black tank seldom gets filled. Of course, use this judiciously or the black tank can be overfilled.
Warren G
Tuesday 3rd of June 2025
We have used a dishpan instead of the sink for washing dishes as you suggested. Then dump the water in the black tank, which we never fill as quickly as the gray. Additionally a little Dawn can’t hurt in there.
TheRVgeeks
Tuesday 3rd of June 2025
Great tip, Warren! Thanks so much.