Grey Water Tank Size

[sealguy77]

Hi everyone!

I'm converting over a 2005 Thomas HDX and am designing my water system. My wife is an amateur baker/cook and having a good supply of water is important to us.

Considerations:
- I am getting a 125 gallon fresh water tank
- We will have a composting toilet.
- We will have a smaller black water tank for urine.

Thanks in advance for your advice.

[T-Bolt]

Hi neighbor! We are in Lafayette.

We have a 40' RE and I am working on plumbing now. Going with 132 gallons fresh, 75 gray, and 55 black.

[BeNimble]

Water is about 8lbs per gallon, 125 gallons = 1000 lbs..so be sure to mount it appropriately and don't let it slosh as even more stress.

[Danjo]

I am super envious of big buses that have that kind of room under them. But no mater how much you have, when you dry camp, you never have enough water.

What’s your grey water tank for? I’ve been wondering why RV manufacturers and everyone else drains the kitchen sink Into the grey tank when that should be classified as black tank material. If the grey tank were used for true grey water it could be dumped on the ground. True grey water is shower water. Everything else is black water.

The reason I bring this up is that if you have a tank just for shower water then you could use this to water nearby bushes via a hose, conserving tank space for black water that needs to go into a dump station.

Regardless of how big your tanks you’re going to become a water saver. Here’s a video of real world water use in a bus.

https://m.youtube.com/watch?v=anB5rhlFUbc

[T-Bolt]

Originally Posted by BeNimble

Water is about 8lbs per gallon, 125 gallons = 1000 lbs..so be sure to mount it appropriately and don't let it slosh as even more stress.

I was planning on using lots of cable ties.

[dzl_]

Originally Posted by Danjo

I’ve been wondering why RV manufacturers and everyone else drains the kitchen sink Into the grey tank when that should be classified as black tank material. If the grey tank were used for true grey water it could be dumped on the ground. True grey water is shower water. Everything else is black water.

Why do you say that? I'm not challenging you, I just don't understand the distinction you are making. Why would sink water be any less grey than shower water?

[Danjo]

Originally Posted by T-Bolt

I was planning on using lots of cable ties.

Dont do that! Use all thread and Unistrut. You’ll also want to add some support under it that spans the surface. I used 16 gauge steel sheet. You could also use plywood if you sealed it really well. I also added protection to the top of the black tank because of where it was. Just think about abrasion and go from there

[Danjo]

Originally Posted by dzl_

Why do you say that? I'm not challenging you, I just don't understand the distinction you are making. Why would sink water be any less grey than shower water?

EPA classifies kitchen sink water as black water. If you dump it on the ground it will stink to high heaven! Shower water won’t stink. You’d still want to plumb that tank to be able to dump at a dump station, but you could also make a hose connection to water bushes with the caveat of being mindful of where you do it.

[Drew Bru]

Originally Posted by sealguy77

Hi everyone!

I'm converting over a 2005 Thomas HDX and am designing my water system. My wife is an amateur baker/cook and having a good supply of water is important to us.

Considerations:
- I am getting a 125 gallon fresh water tank
- We will have a composting toilet.
- We will have a smaller black water tank for urine.

Thanks in advance for your advice.

We've got 100gal fresh and 65gal grey. Wish we'd gone with something like 80 for the greywater, as we find ourselves running out of space in that tank before the fresh needs to be filled again. We also have a composting toilet and do a lot of baking/cooking. If you've got the space for a larger tank, I'd say shoot for an 80% grey to fresh ratio.

[sealguy77]

Originally Posted by Drew Bru

We've got 100gal fresh and 65gal grey. Wish we'd gone with something like 80 for the greywater, as we find ourselves running out of space in that tank before the fresh needs to be filled again. We also have a composting toilet and do a lot of baking/cooking. If you've got the space for a larger tank, I'd say shoot for an 80% grey to fresh ratio.

Awesome! Thank you. Ideally, I'd run out of fresh water and propane about the same time I need to dump grey and black water tanks. I was having trouble finding a good rule of thumb like the 80% ratio. Sounds like y'all have a similar lifestyle as we are planning.

Thanks again!

[sealguy77]

Originally Posted by T-Bolt

Hi neighbor! We are in Lafayette.

We have a 40' RE and I am working on plumbing now. Going with 132 gallons fresh, 75 gray, and 55 black.

Lafayette! Nice! I was reading up on your website and saw y'all skipped the roof raise. If y'all change your mind, let me know. I am just finishing mine and it wasn't difficult at all.

Thanks for the info though. Are y'all using a regular or composting toilet?

[sealguy77]

Originally Posted by Danjo

I am super envious of big buses that have that kind of room under them. But no mater how much you have, when you dry camp, you never have enough water.

What’s your grey water tank for? I’ve been wondering why RV manufacturers and everyone else drains the kitchen sink Into the grey tank when that should be classified as black tank material. If the grey tank were used for true grey water it could be dumped on the ground. True grey water is shower water. Everything else is black water.

The reason I bring this up is that if you have a tank just for shower water then you could use this to water nearby bushes via a hose, conserving tank space for black water that needs to go into a dump station.

Regardless of how big your tanks you’re going to become a water saver. Here’s a video of real world water use in a bus.

Good to know about sink water actually being black water. I'll look into changing things around. Now I am considering if it makes more sense (space and plumbing-wise) to just forego the grey water tank and put everything into a black-water tank.

[T-Bolt]

Originally Posted by sealguy77

Thanks for the info though. Are y'all using a regular or composting toilet?

We are using a standard RV toilet. I can't imagine 8 people in a bus with a composting toilet.

[ChuckRatto]

Seems everyone his responding with their own pro opinion on how to build your bus! Its your bus, you can build for your own anticipated needs and wants! A good rule of thumb is to start with the RVIA code for Recreational Vehicles and go from there. The main thing is to feel the pride of acomplishment when completed!