Size black and grey water tanks for an Ford E-150

Is there room? The black tank has to go directly under the Toilet.

You are best off with a black tank directly under the toilet, for a straight drop into it.

A lot of van conversions use 5 or 8 gallon jugs in a cabinet under the sink for gray water. You could also extend the sink outlet to go through the floor, and then over to a container set outside.

If you google around you will see a lot of ingenious systems for popups. Some use wheeled totes, some use jugs.

I went a took a closer look underneath. The tires are low and require replacement, so I'm not able to thoroughly inspect the undercarriage until it's jacked up.

It does have a drain pipe with spigot for grey water that extends to the rear corner, however I can't see any grey water tank, possibly it's installed somewhere inside.

The frame is approx. three feet wide with ~1/2 of the three feet is the driveshaft and muffler. The rear of the frame has a 25 gallon fuel tank and the front the engine and transmission.

It appears the only space for a black water tank would be somewhere in the middle of the frame on the half without the driveline and exhaust and muffler.

If installing a black water in the middle of the frame would present a problem with the inlet and the outlet (drain). An RV toilet would not have a straight drop to the black water tank which is usually neccsary when installing a RV Toilet. However I remember reading about RV black water tanks that aren't installed directly under a RV toilet.

Though most RVs do have their RV toilet positioned directly over the black water tank for a straight drop there is an option to install a RV toilet anywhere in a RV by using a macerator and pump.

Some macerator are installed separately while others are installed in the RV toilet.

The macerator churns the effluent and pumps it to another location such as a black water tank and/or sewage or septic tank.

I have considered a low flow flush toilet that uses around 1.6 gallons per flush, where a RV toilet uses ~.5 or less gallons per flush. I think a few low flow flush toilet may use closer to 1 gallon per flush. However it's still uses too much water compared to a RV toilet that typically uses ~.5 gallons or less per flush.

Macerators and RV toilets with macerators can be expensive.

However I'm not certain if I would need two macerators as I would need one to pump effluent from the RV toilet into the backwater tank and another pump to push the effluent out of the black water tank.

I'll probably need to look at some installations to figure out a common design.

One problem with installing a blackwater tank in the middle of the E-150's frame is getting the effluent to drain, so it most likely would require a pump of some sort to pump the effluent out of the black water tank.

There are portable macerater units that you connect to the blackwater tank's outlet, churns the effluent and sends it through an attached ~1 inch hose.

RV Holding Tanks

you would be better off using all tanks inside your camper van especially during cold weather months. as long as you keep the van heated nothing will freeze i use 2-5gallon under sink water jugs one for fresh water one for gray water with a water pump to the sink, very easy to use and dump. and a Portable Toilet that is easy to use and dump in any toilet like this Portable Toilet this all works great for me and has down to a -38 degree night (i have a 20,000 btu suburban lp gas furnace also). there are hundreds of ways to do it and a quick google search can find them like this Fresh and Grey Water Tanks

I don't plan on using the B Van during the winters as I have another larger RV that's connected to shore power 24/7 year around.

I'm currently stay full time down in Northwest along the Pacific Ocean where temperatures are relatively mild, rarely drop into the teens during the winter months.

There's alot of humidity and it rains alot but doesn't really get very cold, especially if your located near water such as Pacific Ocean, Puget Sound, etc.

Yes, its would be a big hassle and expense to install a black water tank using a macerater. So I'll probably pick up a Dometic or Thetford 5 gallon porta potti or build my own toilet. There is an article online of some people converting a Thetford Porta Potti into a compost toilet.

How to turn a chemical toilet into a composting toilet
May 31, 2016 / VanSpecies

I've found a few new Dometic 966 series on eBay for under a $100.00.

e.g. https://www.ebay.com/itm/253056969380

I'm uncertain how the the Dometic and Thetford Porta Potties compare to less expensive units ~$50. to $~65.00.

https://www.ebay.com/itm/222904392379

But from reading reviews their not all that well made, some care needs to be taken not to break them. Porta potties potentially have problems with leaking if not handled correctly.

I'm thinking of looking into perhaps a home made composte toilet. Trying to purchase a compost toilet for an RV potentially can run from a grand to over two grand. I saw a less expensive one for around ~700.00.

Have you considered a cassette toilet? These are similar in concept to high-end portables, except that what you take to dump is a removable tank, the cassette. Some want a water supply, others have their own supply tank (to be filled at time of dump).

Composting toilets often need separate disposal paths for liquid waste. In permanent locations, urine is often simple piped to where it dumps on the ground, or else to a separate tank for later disposal. I'm not sure how this fits into a mobile situation, and might be why mobile composters get expensive.

I've had my no-frills Thetford TC 25100 for about 18 years now and the only time it leaked was when I didn't put the top unit back on the bottom unit properly. Only did that once!!

If it ever fails I plan on replacing it with the another 2.5 gallon capacity unit. The larger units might sound good initially but 5 gallons of waste is awful heavy, especially when trying to empty the tank into a 4" dump-tube!!

I have it sitting on top of a custom stand to get the seat-height back up to something reasonable and there is storage in the stand for bowl-liners, tank chem, and toilet paper. Stand and toilet slid into a cupboard when not in use.

I was able to move the van from storage and the person removed all their stuff out of the Van. I was able to take a closer look at the interior.

There is a grey and freshwater tank (with water pump) under the bed, a sink but no toilet or black water tank.

I'm thinking of getting a porta potti as it would be difficult to install a toilet next to instead of over a grey water tank.