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Reusing water helps minimize waste. Photo by Prasit / Getty ImagesDid you know that landscaping irrigation accounts for roughly a third of all household water consumption in the United States? This equates to a staggering 7 billion gallons (26.5 billion liters) of potable water being used on lawns daily [source: EPA]! How can we cut down on this waste? One way is by reusing water. Just like how recycling aluminum, glass, plastic, and paper reduces landfill waste, recycling water helps decrease the amount of water flowing into our sewer systems. A simple method for this is collecting used or untreated wastewater from your home to irrigate your garden.
You'd be surprised by how much water can be safely redirected from the sewer to your garden. A prime source is the runoff from your roof. Many homes are already equipped with gutters, which can easily be modified to collect rainwater in barrels. This water can be stored for use when the weather turns dry. You can also recycle gray water, which includes water from sinks, showers, laundry, dishwashers, and other non-toilet sources. While capturing this water may require more effort, the environmental and financial benefits make gray water recycling a worthwhile endeavor.
Why should you bother recycling water? For starters, it's beneficial for the environment. It reduces the amount of water extracted from fragile ecosystems and prevents nutrient-rich wastewater from being released back into these areas. Although this might sound positive, high nutrient levels in wastewater can actually harm ecosystems by fostering excessive algae growth, which can suffocate other aquatic life. Recycling water also conserves energy by cutting down the need to pump it from rivers, reservoirs, or underground sources, and in some cases, transporting it long distances to meet the needs of dry cities. And if these environmental reasons don’t convince you, there are practical benefits for you as well. Using recycled water can lower your utility bills and is often exempt from usage restrictions during droughts.
Rainwater Harvesting
Did you know how much water flows off your roof when it rains? It’s probably more than you expect. An estimate is about half a gallon per square foot of roof for every inch of rainfall. This means a 1,000 square foot (92.9 square meter) roof can collect around 500 gallons (1,893 liters) of water!
You can easily redirect this water to your garden, especially if your home already has gutters installed. Here’s how you can do it in five simple steps:
- First, you'll need a large container, known as a rain barrel, to collect the water from the downspouts. A 55-gallon (208-liter) food-grade plastic barrel works well because it’s safe from harsh chemicals and won’t degrade. The barrel should be opaque to prevent algae growth. Clean it inside with a bleach solution: 1/8 cup of bleach in 5 gallons (19 liters) of water.
- Next, install a spigot. Don’t position it at the very bottom where debris can clog the flow. Instead, drill a 15/16-inch (2.4-centimeter) hole a few inches above the bottom and attach a 3/4-inch (1.9-centimeter) spigot, similar to the ones on the exterior walls of houses.
- Now, create a platform for the rain barrel. This will allow you to fill watering cans more easily and give the water better pressure to move through a hose. Make sure the platform is sturdy because 55 gallons (208 liters) of water weighs about 500 pounds (226.8 kilograms). Concrete blocks work well for this.
- Once the platform is set up, connect the downspout to the rain barrel. Mark the downspout a foot or two above the barrel. Use a hacksaw or tin snips to cut it and attach a flexible downspout extender. The bottom of the pipe should fit tightly to the barrel to prevent mosquitoes from laying eggs in the water.
- Finally, drill a small hole near the top of the barrel to allow excess water to drain and prevent overflow. You can connect this hole to a hose to redirect the water to your garden or even to another rain barrel. Be sure to place a screen over the hole to keep mosquitoes out.
Some buildings are designed to capture large amounts of rainwater for various uses. For example, the Heifer International Headquarters in Little Rock, Arkansas, collects rainfall into a 25,000-gallon (94,600-liter) tank. The water is then used to power the radiant heating system and to flush the toilets [source: Heifer].
Using Gray Water
Gray water: While it doesn’t sound like the most refreshing drink, gray water refers to the mildly dirty, lukewarm water used for tasks such as washing dishes, showering, and laundry. It’s cleaner and safer than black water, which comes from toilets and often contains harmful bacteria. Although neither type of water is safe for drinking, gray water can serve a useful purpose in your garden.
You can gather gray water from sinks and showers, but the easiest source is from your washing machine. This appliance typically pumps used water into the sewer, but with some adjustments, you can redirect this water to your garden. Start by installing a three-way valve at the end of your washing machine’s drainage pipe. This lets you choose when to send the water to the sewer or to your garden. Once you have it redirected, you can collect the water in a container, similar to a rain barrel. You can then use a hose to water your plants. Alternatively, you can direct the water straight into an irrigation system, though this will require digging and laying down pipes to carry the water to your plants.
Since laundry water isn't fully sterile and may contain impurities, take precautions when using it for irrigation. Only apply it to flat areas where it can soak in quickly, avoiding sprinklers or pooling water. This will minimize contact with humans or animals. Avoid using bleach, liquid fabric softeners, or soaps with sodium or borax when washing clothes, as these can harm plants. To reduce the risks from these chemicals, distribute the water over a larger area and alternate between gray and fresh water. Additionally, be aware that about 30 states have regulations for gray water use, so make sure to check local laws before setting up your system to ensure compliance.
Since gray water may contain viruses and bacteria, some gardeners are cautious about using it for vegetable crops. If you decide to use it, opt for drip irrigation at soil level to prevent the water from splashing onto the edible parts of your plants. If you’re growing root vegetables, it’s best to avoid gray water, especially if they will be consumed raw. While the risk of contamination is minimal, to be absolutely safe, it's recommended to use gray water only on grass or ornamental plants.
