Our region certainly earns its tongue-in-cheek moniker, the Pacific North

wet

, at this time of year. We have ample moisture for the taking and yet most of us let it literally wash down the drain. Come summer when our skies clear and the rain stops, we buy it back to water our gardens. How silly is that?

Jason Garvey, owner of Portland Purple Water, adds that it's inefficient, illogical and wasteful. For a state that prides itself as a leader in the green movement, we trail behind other states when it comes to rainwater-capture legislation and systems. Despite the illusion that our supply of clean water is endless, it's not. Demand from an ever-growing population will outstrip supply by 2028, according to

projections. Rainwater collection is part of the solution. An added bonus: It reduces demand on stormwater systems.

Here are some options and things to keep in mind in setting up a system to capture what falls from the sky for use in your yard.

OPTIONS

Rain barrels

are the least expensive way to get your feet wet, so to speak. Portland Purple Water will install a 55-gallon rain barrel for $95 within the Portland area. You can dress up the blue plastic container with a cedar cover. For a smaller investment, you can install your own from a kit or make your own barrel using a food-grade drum. While it captures the least amount of water, it fills gratifyingly quickly. A mid-August rain can replenish a barrel. Tuck one into a 9-square-foot area near a greenhouse and use it to hand-water plants all winter long. Because rain barrels have low water pressure (less than 4 psi), they are not suitable for use with sprinkler systems. You can increase your capacity by hooking multiple rain barrels together

A cistern

is a better option, installed either above or under the ground (see one caveat about in-ground ones below). Portland Purple Water offers cisterns from 550 gallons -- the equivalent capacity of 10 rain barrels in a 7-by-7-foot space -- to 50,000 gallons. Prices for a 550-gallon cistern, installed aboveground, begin at $995. Water pressure for aboveground cisterns is comparable to that of rain barrels. Although the operating pressure of soaker hoses is about 15 psi, Portland Purple Water has had some success using soaker hoses; once they become saturated, the pressure builds up and water weeps out. Keep the run simple -- short length and few bends -- for best success. Install a pump, either electric or a bicycle-powered pump designed and built by Garvey, to boost the psi to meet drip system requirements.

Another option is the

Rainwater Pillow

, a reinforced polymer alloy product that expands like an air mattress as it collects water. Capacity ranges from 1,000 to 40,000 gallons. It's built like air mattress -- wider and longer than it is tall -- making it well-suited for storage under decks and in crawl spaces. A 1,000-gallon pillow measures approximately 10 feet by 8 feet by 2 feet when completely filled, and requires 1 foot of clearance on sides and top. You can order custom sizes. A 1,000-gallon pillow kit, installed, is approximately $3,000 from Rainwater Recyclers. The kit includes a 1/2-horsepower pump that provides 35 psi, sufficient for use with drip irrigation.

THINGS TO CONSIDER

Site location is a compromise between aesthetics and proximity to point of use, but the best site is where the container can collect the most rainwater in the shortest time.





Overflow will happen; manage it safely to prevent erosion, damage to your home's foundation, or crawl space or basement flooding. The easiest solution is to divert the overflow back into your downspout. Portland's Bureau of Environmental Services offers additional overflow management guidance.

Add a first-flush diverter, gutter screens or another type of filter system between water source and container to keep debris out of your system.

Empty rain barrels and cisterns benefit from an annual scrubbing with water and elbow grease to remove residue (add an anti-bacterial soap such as Dial when necessary). Add a little Clorox if your Rainwater Pillow develops an odor (oxygen levels drop in water stored over extended periods without replenishing). Clean out filter systems as needed. Because these are closed systems, mosquitoes are not an issue.

Can rainwater collected from asphalt roofs be used for edibles? The short answer is "yes." The long answer is that it depends on whom you ask. However, the consensus is that the use of rainwater collected from cedar shake roofs is prohibited. There are scant studies on the purity and use of collected rainwater -- this is a young, still-evolving industry, after all. Consult a professional to get the latest information and to see how it affects your situation.

Check with your municipality and your community regarding restrictions, permits and rebates. Permits are generally not required provided the water is for landscaping use. If you live in Portland and safely manage the overflow from your rainwater catchment system on site, you may be eligible for the Clean River Rewards discount program.

Rain barrels and aboveground cisterns can be tackled by savvy DIYers. In-ground cisterns are more complicated and not just because of excavation needs. If you don't calculate buoyancy equations correctly, groundwater pressure will lift the system out of the ground. In-ground cisterns require a pump in most applications.

Note:

Installation costs include site assessment, preparation and overflow management.



WATER BY THE NUMBERS

The average Portland home

uses more than 90 gallons of water per day. Approximately 30 percent is used for drinking and cooking (potable) and 70 percent is used for showers, toilets, laundry, landscape and other nonpotable uses. Rainwater can fulfill all nonpotable water needs.

Water use spikes in summer

. A 1,000-square-foot garden or lawn that requires an inch of water a week will require almost 7,500 gallons of water over a 12-week period. That same space filled with established, drought-tolerant plants will have reduced water needs. Refer to the history portion of your water bill to determine how much water you need during our dry summer months.

1,200 square feet of roof can potentially capture:

27,375 gallons of rainwater in Portland.

35,250 gallons in Gladstone.

31,125 gallons in Tualatin.

56,025 gallons in Seaside.

To determine how much rainwater you could collect

, calculate the area (length by width) of your roof that will drain to your catchment system. Multiple that figure by your city's average rainfall (type "Country Studies Oregon weather" into a search engine to find this). Multiply that total by 0.625 (per Rainwater Recyclers) to determine how much rainwater you can collect.

The rate of rainwater capture varies

from 0.46 per inch to 0.85 or higher per inch depending on various factors including roof material (metal roofs provide highest yields), tree cover, gutter leaks and evaporation.

A gallon of water weighs 8.35 pounds.

-- Freelance writer and master gardener

RESOURCES



Jason Garvey, owner

Portland Purple Water

8152 S.W. Hall Blvd., #321

Beaverton

503-922-3583

Jeff Williamson

Sales and installation

Rainwater Recyclers

1715 Washington St.

Oregon City

503-723-0209



ONLINE RAINWATER HARVESTING COMMUNITY

Oregon Association of Conservation Districts

737 13th St. S.E.

Salem

503-566-9157



Oregon Smart Guide: Rainwater Harvesting

State of Oregon, Building Codes Division

1535 Edgewater St. N.W.

Salem

503-378-4133



HOW TO MANAGE STORMWATER

Rain barrels

Portland Bureau of Environmental Services



1120 S.W. Fifth Ave.

503-823-7740

cleanriverspdx.org (click on Clean River Rewards, then Rain Barrels