gardening in humboldt

Part 3 of Saving Your Rainwater

Materials for the Collection Part of the Rainbarrel System

We could have asked the local gutter installer to recycle some old parts to us, but a deadline meant we had to buy them instead, along with most of the plumbing stuff. We had some of these parts already but it looks like we still spent about $140 total for this system.

The manifold is the central plumbing that moves the rain water into and out of the barrels, and it is made using PVC pipe. We built it in the form of an upside-down letter T. The 2" diameter vertical part collects the water from the gutter, and the 1" horizontal part distributes the water evenly between the six barrels. This horizontal pipe also has a faucet on one end to draw water from the system. Everything is slip fit except for where the faucet and flex pipe connect to the manifold. There is some gluing involved. Most of the following parts came from Ace Hardware.

From the rooftop down:

• 2 - gutter brackets, $4 each (all gutter parts are plastic)
• 2 - 7' gutters, $8.50 each
• 2 - gutter ends, $4 each
• 1 - gutter drop connector, $6.50
• 1 - gutter drop to 2" round pipe adapters, $7
  
  
• 1 - 5 ft X 2" intake manifold (all pipes and fittings are PVC)
• 1 - 2 X 1" tee for overflow, $4
• 1 - 2" tee, with 1" reducers in the straight ends, $8
• 2 - 7 ft X 1" barrel manifold pipes
• 5 - 1 X ½" tees for the barrel manifold fittings, $3.50 each
• 1 - 1 X ½" end fitting, $3
• 1 - faucet and 1" adapter, $12
• Misc pipe straps, fasteners, primer, glue, etc.

Construction Details and Pictures

The shed has a thin metal wall and we used an assortment of nuts, bolts and washers to attach the collection system.

One important detail—the barrels should be at roughly the same level at the top. It doesn't matter if they are of different heights or widths, or even widely separated, but the tops will have to be kept level horizontally for this to work. The water level in all the barrels will match the level in the lowest one.

After installing its mounting brackets, the gutter snapped into place. It is important that the drop be at the lowest part of the gutter, but it does not have to be in the middle as shown here. The smallest pipe used in this system is the half-inch flex pipe, so we laid quarter-inch hardware cloth over the drop opening inside the gutter to catch the big trash.

This is the 2" drop pipe, and that top tee is the overflow. One barrel had to be set in place temporarily to determine where this tee would be placed because we wanted this opening just below the tops of the barrels. We're going to put a 1" elbow into this overflow without gluing it. Swiveling it will allow us to fine-tune the water height in the barrels.

Do we really need this overflow? No, we could just let the water run through and out of the vented tops of the barrels. But we put this in because this roof collects foreign matter. This overflow will help keep the extra water and most of its trash out of the system, and we will have less maintenance.

North Coast California's climate is that of a temperate rain forest (the giant redwood trees live here). This half of the roof collects enough rain to fill forty rain barrels during the November through March rainy season, which brings us three to four feet of precipitation. That's a lot of rain, as you can see from the picture at the top of this page!.

So if we had all this extra water, why did we stretch the gutter for the entire width of the shed? The night-time humidity during the dry season provides moisture which collects on the metal roof. This adds a few gallons when we need it the most, and that's when that gutter needs to be as wide as possible. We could even add a gutter to the other side of the shed's roof and plumb that into the system when we need it.

Wood strips and straps holds the manifold to the wall. Just plain straps would work, too.

The plumbing is done and the first barrel is in place. We made sure that all of the fittings from the overflow tee to the bulkhead fittings on the bottoms of the barrels are watertight. The water in the vertical drop pipe will always be the same height as the water in the barrels, and a leaky fitting will cause water loss.

Each barrel has a flex pipe to connect to the horizontal part of the manifold. Why the insulation on the horizontal pipe? Several times during the early spring the area enjoys frosty weather, and the insulation will help keep the plastic pipe from cracking. The non-rigid flex pipe does not need insulation. Does it freeze hard where you live? You may then need to drain this for the winter.

Why don't we just connect the barrels to each other? We could, but then all the water would have to pass through every barrel and every flex pipe, limiting the flow, and if one plugged up, we would be in serious trouble. 

Why are we using flex pipe? A number of reasons—the ground moves here, which could cause rigid pipe to break; but more importantly, any barrel (even a full one) can be disconnected from the system by implementing a cap and a plug. There's just enough room to squeeze between the shed wall and the barrels to do simple maintenance work, and there's not a lot of water pressure in this system.

We're done! We checked for leaks, covered the bung holes to keep out the mosquitoes and made sure each barrel is vented at the top. This system is almost two feet off the ground with cinder block support. Note that the overflow tee now has an extension to direct excess water to the French drain located under the barrels.

Water Seeks Its Own Level

So how does this work? Rain water is collected in the gutter and drops down that vertical pipe. When it reaches the bottom it flows into the horizontal pipe, into the six flex pipes and into the barrels. As more rain is collected, the height of the water level in the vertical pipe increases and the water flows into the six barrels to match that height. When this level reaches the overflow tee the barrels will be nearly full and all additional water exits through the overflow. No moving parts and nothing to keep track of.

Simply open the faucet when you want to use the water. The horizontal pipe is fed from the six flex pipes and there's a good flow. The water levels in the barrels (and in the vertical pipe) will drop, allowing the next rain event to refill the system automatically.

Top

• Page 1: Introduction
• Page 2: Putting together the rain barrels (lots of pictures!)
• Page 3: Finishing up with the rainwater collection system (this page)