Rain Harvesting Part II – Planning & Making the Rain Barrel
In a previous post, I’ve discussed various reasons for and legal issues surrounding harvesting rain water. Now here is the nitty-gritty of planning your rain-harvesting storage system.
1. Identify where/how water is leaving your roof. For most, this is where rain gutters leave the roof to run to the sewage line (called a downspout) and are usually at the four corners of the house. You can choose to put a barrel at just one or at all of the downspouts. Some houses built in the desert get such little rain that gutters do not exist. You can install gutters or identify where your biggest ‘drip’ is when the next storm hits.
2. Is there room for a rain barrel next to/under the current gutter downspout? If there is, great… proceed to the next step. Otherwise, you might have to rehang your gutters to send the water to a more convenient place. Water runs down hill, so rehang such that the spot you want is the low point.
3. Acquire rain barrel(s). You can buy fancy rain barrels, but you can also easily build one for under $30 by
- picking up a barrel – You want a food grade (previously held soda syrup=good; previously held chemical=bad) 55-gal drum off of Craigslist or a food distribution place. Most are ugly blue, but you can find white ones here and there and I’ve heard of people spray painting them as well. If you are in Utah, remember that Utah allows 2 each of 100-gal barrels… I’d be VERY tempted to acquire 4 each 55-gal containers and call it good.
- creating an inlet for the water – if there is a already a ‘bung’ or small hole in the top of the barrel, great. Barrels with removable lids, however, will likely need a hole cut in the lid of the barrel about 3-4″ wide.
- installing a 3/4″ hose spigot (from your hardware store) by drilling a 15/16″ hole for the spigot threading just a few inches from the bottom of the barrel. Then screw in the spigot. (You may need teflon tape and/or a bead of silicon to keep it water tight – test with a bit of water)
- covering the inlet hole with window screen mesh (also at hardware store) – DO NOT SKIP THIS STEP. It is a health & safety precaution to (a) limit breeding mosquitoes and their diseases and (2) limit organic matter (leaves) contaminating your water and (3) keep a small animal (or kid) from toppling in. If you don’t have this, you need to empty out the water within 24 hours.
- drilling another small hole big enough to fit a 2 inch drainage pipe for the overflow near the top of the barrel. This would also be a good time to think through where that overflow will go in a series of big storms. You can use a flexible 2″ hose to get the overflow away from your house; ask your hardware store what they suggest to attach the hose to the overflow hole. Portland requires overflow 2 ft from a slab or crawlspace and 6 feet from a basement. It can go back in the storm water system as well, but this should be your last choice environmentally as you are trying to deal with water on site.
4. Gather your materials for disconnecting your downspout – you will minimally need
- a standpipe cap for each downspout currently connected underground
- one or more gutter/downspout elbows (and possibly flexible gutter length) if you need to slightly change the direction of the downspout to be over the barrel
- a flat surface to place your barrel on. Concrete pavers will do. You do need the surface to be higher than your garden and thus some like to elevate a bit on concrete blocks. This can also allow for putting a watering can underneath a spicket. If you do more than one tier, change the orientation of the blocks 90 degrees each tier. Either way, it needs to be level because a full 55-gal drum weighs 400 lbs and you want stability.
One final design considerations is planning for winter. You will need to empty your rain barrel with hard freezes as expansion of ice will crack the barrel. In Portland, we get so few hard freezes and have good overflow solutions for the massive amount of winter rain that most people to empty the system before a freeze and closely monitor to keep it drained during the storm events where rain to snow is likely. But in a place like SLC, you probably want to empty the barrel and take it ‘off-line’ until spring. This requires thinking through how to reconnect your downspouts or (as I’ll show in the next post) run your downspout to your lawn for the winter. If you want a more seamless solution where you flip a switch, google ‘downspout diverter.’
Up next… installing barrel/disconnecting downspout.