How Long will a Grey Water Tank Last?

When picking out the right trailer for you, storage tank sizes can be a big factor of deciding on the right trailer. The length of time a grey water tank will last varies depending on users and how it is used.

How long will a gray water tank last?

The size of your grey water tank and number of users in your travel trailer will dictate how long your grey water tank will last. Typically a couple can get 2-3 days if they are living as normal. Showering, washing dishes, and washing hands will be the biggest users of your grey water tank.

We will show you with typical use how long you can expect to get out of your RV grey tank, as well as conservation ideas to make your tank last longer.

RV Grey Water Tanks Explained

The length of time you will get before dumping your gray water tank will depend on the size of the tank as well as the number of users staying in the travel trailer. According to, the average household user uses 80-100 gallons per day. This includes showers, baths, toilet flushing, clothes washing, etc. Luckly we are in a RV, not a household.

In your RV, you will use significantly less than a household user. If you take two showers in your RV for 4 minutes each, expect to use 16 gallons of water. This will also fill 16 gallons of water into your grey water tank. If you fill your sink with 2 gallons of water to wash dishes for all three meals a day, add another 6 gallons of usage. Remember all of those times you wash your hands after the bathrooms, add another 2 gallons per person per day.

With the sample usage above, you could add 26 gallons of water in a day. If you have a 25 gallon tank in your RV as we do, you are full after a day.

Using the table below which gives a range of gray tank sizes based on RV model, your grey water tank will last from 1-3 days. This number can be greatly increased with some water saving tips detailed below.

RV Make / ModelGrey Water Tank Size in Gallons
Winnebago Micro Minnie25
WInnebago Minnie41
Winniebago Minnie Plus69
Jayco Jay Feather30.5
Jayco Jay Flight19.9
Keystone Bullet 30
Forrest River Rockwood 30-60
Dutchman Aspen Trail38-84

How much water does a shower use in an RV?

We upgraded our trailer to a lower flowing Oxygenics shower head which delivers more water pressure than the stock head. The shower head that came with our RV used about 2.2 gallons per minute and had horrible pressure. The Oxygenics head is rated for 2.0 gallons per minute or GPM. The new head will save about one gallon of water per 5 minute shower. This means, if you are taking a 5 minute shower, expect to use 10 gallons of water.

How to conserve water in a travel trailer?

There are many ways to conserve the capacity of your grey tank in your RV. The gray tank gets filled from washing dishes, hands, and showering.

Washing Dishes

When you wash dishes, buy a Rubbermaid or other plastic container that will fit in your travel trailer sink. Use this for washing and rinsing dishes in, and dump outside when finished. This can save 1-2 gallons every time you wash dishes and you can reduce the dish water filling your grey tank totally. If your travel trailer has an outdoor shower, you can use this as well to wash dishes or other items.


The same with your dishes, you can use a plastic basin to catch your hand wash water and dump outside. We also use the outdoor shower to wash hands if we are cooking or after a hike. Using either of these techniques, you can cut your gray water usage totally.


I have not found a great way to catch water in the shower yet, but you can greatly reduce it. Replacing your shower head with a very low flow head will save a significant amount of water.

Also, when you take a shower, turn the water on to wet your body. Turn the water off and lather up. Turn the water back on to rinse the soap off and enjoy your sailor shower. If you can get by with only 1 minute of water usage, you will only use 2 gallons of water greatly reducing the amount that will go into your grey water tank.

If you use the techniques above and have the same 25 gallon grey water tank, two people could last 6 days showering each day with some leftover capacity. If you shower at a campground, or do not shower every day, you can get even longer.

How much water does my RV sink use?

The sink in your RV will dump directly into your grey water tank. The usage can be great if you have a lot of hand washing and dishes to wash. If you fill up your sink basin to wash dishes, you can add a gallon or more of water into your grey water tank each time.

What happens if your grey water tank fills up?

One thing you never want to happen is to have a grey water or black water tank fill up and overflow. Our grey water tank overflowed once while we were camping. It must have been just about full by night. Our hand washing from the night as well as cooking in the morning added enough water to fill up the tank and overflow about 2″ of water in the shower pan. Luckly we caught this before it overflowed and caused any damage.

How to empty gray water tank?

Gray water tanks should always be emptied after the black water tank. This will clear out any debris left over from your black water dump. Follow these steps to empty your gray water tank:

How to Empty your Grey Water Tank

  1. Put on disposable gloves
  2. Hook up travel trailer to dump station with a sewer dump hose
  3. Pull gray tank valve open and wait to fully drain
  4. Close grey tank valve
  5. Run fresh water through sewer hose if available
  6. Put away sewer dump hose

Learn more about how long a Fresh Water Tank will Last

Read more about how long a Black Water Tank will Last

Related Questions

What is grey water tank?

A grey water tank is a holding tank that fills up with wastewater that is used from your kitchen sink, bathroom sink, as well as shower drain.

Should I leave grey tank open?

You should never leave your grey or black tank open. Leaving your tank valves open will expose your RV to dangerous sewer gas smells. Also, if your tank was left open, when you dump your black tank, you will have no water to clean out your hose after leaving you a smelly water hose.

Can I dump grey water anywhere?

You should only dump grey water in an approved sewer dump station. Grey water has bacteria which can be harmful to people or animals shall they come in contact. If you are in a pinch, empty gray water into a bucket or portable wheeled dump station and dump in an approved station.

Whats the difference between black water and grey water?

A grey water tank catches waste water from your sinks and shower, and could be filtered and used for watering plants. A black water tank only takes water disposed of from the toilet. Black tank water should never be used or filtered for anything. Black water should always be disposed of properly.

Get MORE out of The Savvy Campers Directly to your Inbox!

Be the first to be notified about FREE tips, hints, coupon codes, and email-exclusive information. All for FREE!

Similar Posts