Catching rain water ... inside the building

I have a question for you more experienced rain water collectors out there.

In my newly converted garage/pottery studio I would like to set up a few 55g barrels to catch water and serve as my main working sink (non-potable use only).  Here's the problem: it's a garage.  Zero plumbing.  No drain or pipes inside.

What I'd like to do is run the gutters inside to the barrels on a sturdy shelf above the sink, gravity feed them down to the sink, and drain them back out through the wall into a gravel gray water trench and rain garden.  Here are my questions:

1.  I need to cut at least two holes in my wall: one up high (water in) and one down low (water out).  What advice do you have for making sure these wall holes are re-sealed around the cuts once the plumbing is run through it?

2.  I don't want to flood the studio so I want a very safe overflow.  Should I overflow the barrels down the drain or have a separate overflow pipe and hole through the wall?  Am I correct in assuming the overflow pipe needs to be at least as wide as the inflow pipe so it doesn't fill faster than it can drain?

I'm doing this all myself with perhaps a friend or two helping.  I'm pretty handy, but plumbing is not something I have a lot of experience with, so simple solutions are better.  Thanks in advance for your help!

In southern Europe we remodeled a couple of houses that use a similar system to what you describe.  These systems have been in place for hundreds if not thousands of years.

What happens is the water is collected on the roof tops.  You will notice from the photos that the roof tops are flat and have short walls to contain water during the rainy season.  What is not noticeable is that the roof tops all slope into a drain pipe that goes through the house and underneath the house.  This cistern under the house is a masonry tank big enough for someone to get inside to work on.  It is coated with some type of cement like material that will not contaminate the water. 


From this cistern, the household  obtains all the water that they need.  It is drinkable and used for other purposes.

Yes, you need two holes.    The bottom of the drain hole needs to be lower than the basin so it will drain out.    I would use an exterior water proof caulking to seal around the holes.  Make sure you do not hit electrical wires or other pipes/wires when you make the holes.

A shut off valve has to be installed to prevent the cistern from over flowing.  This can be done outside or inside.  Inside is more convenient but outside is safer if you are worried about water damage to the interior of your room. 
Also remember to support the barrel.  That much water is very heavy.  You may need it up off the ground so as to let it gravity feed into your sink.  Make sure it will not fall over or crush anything or anybody.

I hope that helps.

Thanks for the reply, and the bit about the shut off valve.  I'm hoping to convince a friend of mine to help me with the details.  Maybe I'll post once I've got it going to let people know how my system works.

A full 55 gallon drum will weigh close to five hundred pounds, including the weight of the barrel, so definitely build a sturdy support for those barrels!

Kathleen

maybe consider setting the barrels on the floor instead of going to the trouble of making extremely burly shelves for them.  there are pumps that thread into the bungs of just about any 55-gallon drum.  it would mean pumping by hand instead of just turning on a faucet, but the effort you'll save on installation will be substantial.

I'm planning to do something similar. I'm going to have a cob structure with a metal roof, and I want to use the rain water for washing at a sink.

First I had a crazy idea to imbed the rain barrel sideways in the cob wall, and keep the whole thing gravity fed. But I'm worried that it will be hard to keep a good seal where the barrel comes through, with the shape and weight changing as water goes in and out. Also it could freeze in winter.

So now I'm thinking I'll run the water through the wall to a barrel on the floor under the sink, or several barrels in parallel. (A roof will collect 55 gallons pretty fast!) I can have an overflow pipe coming out of the barrel slightly below the pipe that feeds it, which will take extra water back out through the wall, with no need for a shutoff valve.

Also, if people are going to be using the sink to wash stuff, it would be great to have a foot pedal pump so they can keep their hands free. I poked around online and found this foot pedal pump made for boats, the Whale Gusher Galley Mk3.

Unless you all can come up with a better idea, I'll try it and see how it works.

Ran Prieur wrote:
Also, if people are going to be using the sink to wash stuff, it would be great to have a foot pedal pump so they can keep their hands free. I poked around online and found this foot pedal pump made for boats, the Whale Gusher Galley Mk3.

that looks like a pretty slick pump.  much more convenient than a hand pump.  around $100 isn't terrible.  I've seen foot pumps in port-a-johns, too.  they don't work very well, but I would bet they're cheaper.

your idea to build the barrels into the wall sounds kind of neat, though I'm sure you're right about the complications involved.  what about building in two layers of barrels stacked vertically?  the lower layer can stay full all the time and function as a heat sink.  the second layer is supported by the first and gravity feeds to your sink.  I believe the HDPE drums are stackable if they're in good shape, and I'm sure that steel drums are.  you would still have the freezing issue, but if they aren't exposed to the exterior, you might get by depending on how your structure is used.

the floor might still be your best bet, but it can't hurt to explore some other ideas a little bit.

You can also build a cistern underground below the frost line.
These can be lined with some sort of masonry.
That way you can eliminate the dreaded plastic and it can be bigger.

Thanks everyone for all the advice!

I love the idea of the foot pump.  I wasn't super thrilled about having to support that much water up above us.

I've already got the barrels which is why I'm using them.  Doing a whole underground cistern would be pretty expensive!  We've got about nothing to spend on this, we're scavaging all the parts.

No fear, this is by no means modern plumbing-

1.  I need to cut at least two holes in my wall: one up high (water in) and one down low (water out).  What advice do you have for making sure these wall holes are re-sealed around the cuts once the plumbing is run through it?

Use a hole-saw only the diameter of the pipe- if I were doing this, I would cut a square piece of cedar, say from a 1X6, put a piece of copper flashing over on edge, and bend it over the face 1/4" or so to make a drip edge- cut a hole for the pipe with the hole saw in the center, and then cut the 5.5X5.5" away from your siding, so the square with the hole in the middle is inset to you siding- nail, and caulk this in- put a similar piece of wood on the inside- before you put either plate in or out- line the hole with vapor barrier which will be tacked under the "plates" inside and out, once the pipe goes through caulk around it in and out- this should require only a fine bead.

2.  I don't want to flood the studio so I want a very safe overflow.  Should I overflow the barrels down the drain or have a separate overflow pipe and hole through the wall?  Am I correct in assuming the overflow pipe needs to be at least as wide as the inflow pipe so it doesn't fill faster than it can drain?

Do this just like a sink, drill a hole in the barrell 6" from the top and right at the bottom- connect the tub you have coming off the top hole to the one coming off the bottom so they exit the building through one hole. I would make the drain pipes larger than the fill, for the reason you cited. 45 degree jogs are better than 90 degree ones with gravity- and make sure you have a good cover (screen?) on the pipe coming in.