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How to Empty RV Tanks – Dumping Guide

February 15, 2024

Did you know that RVs have three separate water tanks? There’s one for fresh water, one for black water, and one for gray water.

The freshwater tank supplies the showers, sinks, and toilets, while the gray tank is filled with water that’s been used in the shower and sink. As for the black tank, it collects everything that’s flushed down the toilet.

Not only do these tanks keep things sanitary when you’re traveling in your RV, but they also allow you to clean cook, and shower.

The only thing is that they do need to be dumped regularly – ideally, once every 3 to 5 days, or when they’re two-thirds full. That will prevent waste from building up, which can lead to odors, clogs, or misreading sensors.

How do you dump your RV tank? Where do you do it? Which tank should you start with? For the answers, be sure to keep reading.

We’ll be going over everything you need to know below!

How to Dump the RV Black Tank

how to empty rv black water tankIdeally, you want to start by dumping the black tank. That way, you’ll be able to use the gray water to flush out the hose.

To do that, you’ll need to locate free RV dump stations, which can be found in most commercial campgrounds.

You’ll also need a pair of reusable rubber gloves, a sewer extension hose, a sewer adapter, a dedicated garden hose, and hand sanitizer. Sanitizing wipes is also a good idea for when you’re finished.

Start by putting on the gloves and removing the drain cap. In most cases, the black and gray tank will have the same outlet but different valves.

Once the cap is open, attach the hose to the dump station. You’ll also need to attach the clear hose adapter to the outlet, which will then go on the RV sewer hose.

Secure the hose in place and open the black tank valve. The tank should be emptied within a couple of minutes.

While the valve is still open, you can flush the hose by opening the gray tank valve. If you have access to water, you can also flush the system with that.

Last but not least, connect the garden or freshwater hose to the black tank system and use it to rinse out any residue and buildup inside the tank. Seeing as how it will get dirty, it’s best to have a dedicated fresh water hose for the task.

When you’re finished, pack everything up and close the valves.

Tip: It’s best to use a sewer hose support if you’re going to be hooking up in a campground for several days. That’ll allow you to dump the tanks without having to lay the hose directly on the ground.

Rather, it’ll be on the support, which will help improve flow and reduce the possibility of a clog.

How to Dump RV Gray Tanks

how to dump rv grey water tankThe gray tank should be emptied once you’re done with the black tank. The process is similar to that of the black tank. Simply open the gray tank valve with your gloves on and allow the water to drain before closing it again.

Alternatively, you can dump the RV gray water into a toilet if you’re at a campground with toilet facilities (you may need to ask the campground staff first). To do that, you’ll need some five-gallon buckets.

Using the bucket, collect the gray water five gallons at a time and dump it into the public toilet.

Maintaining the Fresh Water Tank

The freshwater tank is the least scary out of the three but also needs to be maintained now and then.

First and foremost, make sure to use a potable water hose when filling the fresh water tank. They’re easy to distinguish because they’re white.

If the tank develops an odor, you may need to clean the tank with bleach. As a general rule, you want to add 1/4 cup of bleach for every 15 gallons of fresh water.

Once the bleach is in, run the water. Continue until all of the bleached water is out and let the tank sit for 24 hours before refilling.

How to Find RV Dumping Stations

Some RV dump stations will be free while others will require a fee. Some popular spots that have a dump station include:

National Park Campgrounds

Most national park campgrounds in the U.S. will have an RV dump station, though it’s not guaranteed. To be sure, you can always check the NPS website for that particular campground before making your way there.

In some cases, the dump sites will be free even if you’re not staying at the campground.

RV Parks and Resorts

finding RV tank dumping sitesAll RV parks and resorts will have a designed dump station. If you’re staying at the park, the fee to use the dump site will likely be included in your nightly rate.

If you’re not staying at the resort or park, you may need to pay a flat fee. We recommend calling ahead of time to confirm.

Gas Stations and Truck Stops

Most gas stations and truck sites will allow you to dump your RV tanks for a fee. Depending on the location, it can range anywhere from a few dollars to $30.

RV Supply Stores

Local RV supply stores and dealerships may have a dump station available. If they do have a station, it’ll likely be free – give the location a call to find out.

Bass Bro and Cabela’s Locations

Many Bass Bro and Cabela’s locations in the U.S. have a SaniDump, where you can empty your RV tanks for a fee (you’ll need to pay for a code at the cashier before using it).

Finding a Free RV Dump Station

Many RV dump stations are free – if anything, you just need to know where to look. If you’re in a new area, we recommend using the app Allstays. It’ll let you find many services including campgrounds, parks, and dumping stations with or without internet.

To find a free dumping station near you, filter by “RV Dumps” in the app and zoom into your current location. Tap on each dump site result and you’ll be able to see whether or not it’s free under the location details.

And remember, not all free RV dump sites will have potable and non-potable water. Some will only provide you with a sewer connection, in which case, you’ll need to provide your own. When in doubt, you can always call and ask ahead of time.

Other Tips For Those Living the RV Life

Here are a few things to keep in mind when it comes to emptying gray and black tanks.

Follow the 2/3 Rule

Start planning for your next dump as soon as your RV black water tank hits the 2/3 full mark. That’ll give you enough time to find your next dumping site so that you won’t have to worry about it overfilling.

You don’t want to dump before the tank reaches 2/3 full either, otherwise, you’ll only be dumping the liquid and not the solid RV waste.

Close All of the Windows

rv tank dumping tipsClose all the windows before you even reach the dump site. The last thing you want is for your RV to smell like a dumping station.

Similarly, you want to close the vents – that’ll help keep the noxious smells outside.

Invest In Some Good Gloves

Invest in a good pair of rubber gloves. For example, you can opt for some heavy-duty reusable gloves or some disposable ones – either one works.

Keep them in the RV and make sure they’re accessible so that you can reach for them once you get to the dump site. They’ll keep your hands clean during the dumping process, which you’ll be thankful for.

It’s also a good idea to get some sanitizing wipes as you never know when you may need them.

Invest In a Good Sewer Hose

A good RV sewer hose is a must if you’ll be dumping the tanks multiple times. Ideally, it should be made of an extremely durable material such as polypropylene, which is both crush and puncture-resistant.

And be sure to replace it now and then – approximately every 36 months, or if you drive the RV full time, every 24 months.

We also recommend keeping a backup sewer hose in the RV just in case the in-ground sewer drain is farther away than usual at a dumping site.

A sewer hose support system is also a good idea if you’ll be staying at a campground with full hookups for extended periods. Just make sure everything is secure before you proceed as the last thing you want to deal with is a black water tank spill.

Install a Twist-On Waste Valve

A Twist-on waste valve will not only protect you from getting wet when you’re emptying the tank but will also provide an extra gate in case your black and gray tanks start leaking.

It’ll also equalize the gray tanks so that you have to dump less often. They’re not that expensive either – you can easily get one for under $25.

Rinse the Sewer Hose

While the sewer hose is still connected to the system, spray it down with a non-potable water hose. Be careful not to splash yourself. Wear some personal protection equipment, if necessary.

After spraying the hose, drain the leftover liquids into the sewer before disconnecting the hose. Wipe down the ends of the hose with sanitizing wipes.

Treat Your Holding Tanks

If you can, use an RV holding tank treatment after emptying your black and gray water tanks.

We highly recommend ACTIVE Holding Tank Digest Treatment – it contains non-pathogenic living bacteria and enzymes that will digest and liquefy solid waste inside the tank.

Not only will it keep odors at bay but it’ll also make sure everything flows smoothly until your next dump. That way, you won’t have to worry about dealing with clogs or back-ups.

It’ll also help maintain sensor performance.

Don’t Remove the Sewer Hose Right Away

how to empty RV tank hoseDon’t remove the hose right away. Make sure the tank is empty before doing so and even then, you want to wait a few minutes – that’ll allow the excess water to drain out of the black tank.

And be careful when you’re removing the sewage hose – there might still be some excess build-up or water near the valve. To prevent spills, keep the hose facing up.

If you do end up spilling some, make sure to clean up right away with a cleaner or sanitizer.

Level the RV Before Dumping

Many dump stations have uneven pavement, which can affect the dumping process. To prevent that, you want to level the RV before starting. Put the jacks down, if you have to.

Alternatively, you can invest in some rubber leveling pads or blocks, which will keep things level so that you can empty the tanks properly.

RV Tank Dumping Guide – FAQs

How often should you empty an RV septic tank?

how often to empty an rv tankAs a general rule, you want to empty your holding tanks when the tank is two-thirds full, or every 3 to 5 days. Keep an eye on the sensors – they’ll let you know when it’s time to go to a dumping station.

What’s the difference between the grey tank and the black tank?

The gray tank collects water from the shower and sink while the black tank is filled with everything that goes down the RV toilet.

Keep in mind, however, that some small RVs may only have one wastewater tank, which collects both gray water in addition to everything that’s flushed down the toilet.

Do you have to pay to use a dumping station?

Most dump stations are free. However, some may require a charge, or if you’re staying in an RV park, it may be included in your nightly fee.

Can I put bleach in my black water tank?

can you clean an rv tank with bleachNo, you should never put bleach into your black tank.

Not only will it kill off the naturally occurring bacteria that’s responsible for breaking down solid waste in the tank but it’ll also damage the seals that are designed to stop odors and leaks from getting out.

Why is my RV’s black water tank leaking?

Your RV’s black water tank may leak if the toilet’s dump tube is not properly sealed where it enters the tank. Leaking can also occur if the tank sensor isn’t tightened properly.

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Marcus Washington

Marcus Washington is a well-rounded expert in RVs and campers. With a wealth of experience, Marcus shares his expertise through his valuable guides, helping enthusiasts and newcomers alike navigate the world of mobile living. His advice covers everything from maintenance to maximizing space, ensuring every road trip is smooth and enjoyable. You can trust Marcus to guide you in your RV and camper adventures.

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