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Other water-saving strategies.

Other water-saving strategies If conservation measures don't stretch your water far enough to save the garden, you have another option: gray water. The term refers to household water recycled from showers, bathtubs, bathroom sinks, and washing machines. Gray water collected from all these sources can supplement your garden's water supply by at least 100 gallons per person per week.

Some household water isn't fit for reuse. For instance, much of the water from diswashers and kitchen sinks (except rinse water) is contaminated with grease a nd food particles. Toilet waste water, called "black water," should never be collected. (on the other hand, tap water collected while it warms up is considered clear water.)

Even the use of "clean" gray water raises safety concerns, but laws have been changed in the last few years to permit its use. Here, we examine the issues of safety and legality, and offer some guidelines for collecting and distributing gray water to the garden.

Is gray water safe?

The primary concerns stem from gray water's highly variable quality and possible contamination by unhealthy bacteria and viruses. (It's worth noting that health officials we consulted knew of no documented cases of illness caused by gray-water use.)

The health risks from gray water are minimal if you collect and apply it properly. Never collect wash water contaminated by soiled diapers or by people with infectious diseases, or used in poultry or wild game preparation. Also, avoid using greasy, soapy water full of suspended solids.

Follow five basic precautions. Always use gray water the same day it's collected. Don't apply it where people will come in contact with it. Don't let it puddle or stand where it won't be absorbed quickly. Don't spray it or sprinkle it. And wear rubber gloves whenever you handle gray water or equipment that comes in contact with it.

Is it legal?

In the past, health officials have frowned on the use of gray water. But with decreasing water supplies, some are allowing more leeway and advising on proper use.

In 1989, Santa Barbara County supervisors amended building ordinances to allow permanent use of gray water--and to allow (with a permit) minor modification of waste-water pipes to collect it. San Luis Obispo adopted the same guidelines in June 1990.

Many other counties throughout California either are going to adopt some sort of guidlelines or are choosing to ignore gray-water use. In the rest of the West, communities usually have no laws specifically about gray water, although most building codes prohibit altering household plumbing without a permit.

For specific rules in your area, call your building, health, or water department.

What can you use it for?

Many of our readers report that they've been using gray water on their plants since the 1976-77 drought with few side effects. Most plants do well on gray water and will not be affected by mild soaps or shampoos.

You can use gray water to irrigate fruit trees and ornamental plants, but don't use it on most vegetables (see box at right) or to wash paved surfaces. Also, don't apply it to seedlings, container plants, or acid-loving and salt-sensitive plants such as azaleas, begonias, camellias, ferns, gardenias, and hydrangeas.

If you collect gray water, don't wash strong chemicals down the sink, such as products for opening clogged drains and products containing boron, chlorine, or sodium. Water softeners use sodium--don't collect water that has run through one.

Of the standard laundry soaps, liquid detergents have less sodium than powdered ones, and biodegradable ones are usually the least harmful.

A laundry soap specifically designed for use when collecting gray water costs $9 a quart, $25 a gallon, plus shipping and tax, from Real Goods, 966 Mazzoni St., Ukiah, Calif. 95482 (also in some natural foods stores). It contains only trace amounts of harmful sodium and has beneficial nitrogen, phosphorus, and potassium.

Even if you're careful about product use, small amounts of sodium and other potentially harmful substnaces may still build up in the soil and raise the soil's. pH, especially if heavy rains don't come in winter. (A soil test can determine sodium and pH levels.)

To help leach harmful substances away, you can alternate irrigations between fresh and gray water (if you have enough fresh water to do this) or flush the soil twice a year with a heavy irrigation.

To lower the pH of your soil, work in 3 to 5 pounds of fineground soil sulfur per 100 square feet and till in plenty of organic matter.

In clay, sodium can also make soil sticky and hinder drainage. Spade into the top several inches of soil 5 to 10 pounds of agricultural gypsum per 100 square feet.

How much gray water

can you expect--and

how do you collect it?

Washing machines use 35 to 70 gallons of water per load. For showers, low-flow heads range from 1 1/2 to 3 gpm (gallons per minute), standard heads from 5 to 8 gpm. Weekly average for each bathroom sink is 14 gallons per person or more.

To figure how many sources to tap into, determine the water needs of your plants in gallons (your cooperative extension office may be able to give help).

Before constructing your own system, check local building codes. Alterations must be approved by a building inspector (washing machine plumbing may be excepted). Always provide for overflow into the sewer line in case the gray-water system backs up, and install a check valve between the tank and the sewer line to prevent sewage backup into the tank.

One of the easiest kinds of collection systems to install (pictured at far left) connects to a washing machine. If the tank sits below grade or the garden slopes up above the outlet, you need to install a sump pump.

Buy one strong enough to get water to the farthest irrigation point (pumps are rated for discharge in gallons per minute or hour, and for "head"--the height they can lift water). Add another check valve between the pump and irrigation line to prevent water backup.

To collect water from main plumbing lines on showers, pipes must be accessible from a crawl space or basement.

How do you get water

to the garden?

Health officials believe that the safest way to apply gray water is below the soil surface or under 4 inches of mulch--through drip irrigation or mini-leach field. Below-surface applications eliminate human contact, and the soil filters out any harmful organisms.

You can run water directly from the source into the distribution system (although you shouldn't apply gray water while it's hot). But most users collect the water in containers first; this gives them control over distribution.

To prevent buildup of residue in tanks and distribution systems, it's best to filter gray water at the inlet to the tank.

If you're using drip irrigation, filtering is critical to prevent emitters from clogging. Place a filter on the tank inlet and use a 200-mesh drip-irrigation filter at the outlet, along with a backflow preventer and pressure regulator.

Clean filters as often as necessary to keep water flowing through them. for fabric-type filters, let them dry, turn inside out, remove the sediment, then flush with clear water.

No matter how well the water is filtered, storage tanks need cleaning periodically. To clean, flush with fresh water.

If heavy rains come in winter, shut off gray-water systems so the rain can leach sediments from the soil.

Precious as liquid gold to many gardeners during dry times, clear water you collect and save can pay dividends to your garden for months. A few buckets of cold shower water each week can keep several container plants blooming lustily; even an occasional bucketful can help a drought-stressed landscape plant survive.

Here are ways to capture and store clear water, which might otherwise drain away.

Capture it outdoors,

from downspouts

One way to quench your plants' thirst is with rainwater-if and when you're lucky enough to get it. Every house that has a rain gutter and downspout has a ready-made collection system; all you need is a "rain barrel"--a 30- to 35-gallon heavy-duty plastic trash container ($10 to $15 at hardware stores).

You may want several barrels; during a spring storm with rainfall totaling just less than an inch, one homeowner filled seven 32-gallon barrels--a total of 224 gallons of rainwater. That's enough to irrigate ten 10-inch pots three times per week for seven months, or to irrigate 18 azaleas in soil basins 18 inches wide and 4 inches deep about once a week for five months.

With more barrels, you could collect up to 1,500 gallons from 1 inch of rain on a 2,000-square-foot roof.

Place a rain barrel under the downspout most convenient to the plants you'll be watering. You may need to shorten the downspout by about 4 feet and angle it out slightly from the eave to aim runoff into the container. Position the barrel where there's adequate drainage to handle spillover. A screen over it will keep leaves from washing or blowing in and fouling the water.

To water plants, ladle stored water into a small bucket or watering can. Or use a submersible pump attached to the hose. If you want to install a spigot near the bottom of the barrel, you'll have to elevate the barrel. Give it firm support: a 32-gallon barrel full of water weighs nearly 270 pounds.

Capture it indoors, from

showers and sinks

How much water goes down the drain while you wait for water to warn up? How much could you save for watering landscapes or container plants? To find out, we collected water in five California households and did some test-irrigating.

You can collect cold, clear water at three p laces: the kitchen sink, the bathroom sink, and the shower. How much water goes through a faucet before it gets warm depends on how far the faucet is from the water heater and how long it's been since the heater was used. Consequently, the amount of water that can be saved varies widely.

In our test houses, individual showers and sinks delivered between 3 quarts and 4 gallons of water before getting warm. Based on those results and a conservative estimate of two showers and two sink uses per day, possible savings amount to at least 21 gallons a week and as much as 112 gallons.

If, for example, you saved 40 gallons of clear water a week, how far would that go in the landscape? It could be enough for one normal watering of about 150 ten-inch pots, 80 three-gallon containers, 8 to 10 fruit trees growing in half-barrels, or 16 to 20 tomatoes or azaleas.

Keep a bucket handy under the kitchen sink, and several in bathrooms. Store any excess water your plants may not need right away outdoors in barrels like the one pictured at left.

A word about storage

Keep a tight lid on the barrel to prevent mosquitoes from breeding inside. In warm climates, protect barrel-stored water from excessive heat buildup (hot water can damage plants) by keeping it in shade. If the barrel must be in sun, choose a light-colored one, which won't absorb as much heat.

Avoid using runoff water from freshly treated wood roofs to water plants; it might contain copper naphthenate, which could damage young plants and seedlings.
COPYRIGHT 1991 Sunset Publishing Corp.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1991 Gale, Cengage Learning. All rights reserved.

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Title Annotation:Sunset Drought Survival Guide for Home and Garden; includes related articles
Date:May 1, 1991
Previous Article:Gardens that are designed for drought.
Next Article:In three steps, a new kitchen and family room.

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