Gray water is wastewater from washing machines, showers, bathtubs, spas, sinks, washing machines, dishwashers and sinks, which can be used to water garden plants. It does not include water from the toilets, which are called aguan negran. Learn how to use water from the washing machine in the garden, known as recycled or gray water.
Introduction
With water restrictions in many areas, using gray water in your garden can help you save hundreds of gallons of water a day, keeping your wallet happy and the planet even happier.
Washing machines account for almost a quarter of domestic wastewater: between 40 and 200 liters per wash (depending on the machine).
So if you have a very thirsty washing machine and you wash it six times a week, you can send up to 1,350 liters of clean, drinkable water down the drain every week (with an annual consumption of 70,180 liters!).
If we add the water for the dishwasher, shower and bath, we soon reach 4,000 liters per week for an average family of four. Find out how to use washing machine water in the garden.
Safety tips for gray water
Do not store raw gray water for more than 24 hours; if you can’t use them, don’t keep them.
The ideal is to mix the gray water with clean water, half and half before watering the garden, this helps to reduce the concentration of chemical substances.
If untreated, limit their use to shower, bath, and wash water (preferably rinse water only). Cooking water contains fats and solids that can harm soil and plants.
If someone in your family has the flu or another contagious illness, stop using gray water until they get better.
Do not water herbs, vegetables or potted plants without access to other moisture. Gray water should only be used as a supplement.
Keep gray water under the cover next to the plants: this helps prevent evaporation and keeps it away from children and pets.
To avoid possible health problems, it is not recommended to use laundry water or other gray water on vegetables or edible plants.
Avoid using water from washes that have heavily soiled loads, for example diapers.
Start in a small area and make sure the plants or grass are acceptable.
Try to use biodegradable detergents, you can also make your own natural detergent for laundry.
Is washing machine water safe?
In our washing machine detergent reviews, we test the wash water for chemicals that can harm your yard. We’ve found that the components most likely to cause problems are phosphorus, salinity, sodium, and pH to varying degrees.
Match
Small amounts of phosphorus can be useful to plants and it is one of the main components of fertilizers.
But when it reaches our waterways, it can cause algae overgrowth, leading to toxic algal blooms. The effect on soil varies according to soil type.
Clay soils can support more phosphorus because phosphorus binds to clay minerals and is not leached out.
In sandy soils, excess phosphorus can seep into groundwater.
Fortunately, or we could sensibly say, modern detergents no longer contain added phosphates, so this problem is a thing of the past.
You go out
All laundry detergents contain salts, usually sodium salts such as sodium nitrate, sodium sulfate, sodium phosphate and sodium silicate, making them very salty.
Sodium is especially harmful not only to plants, but also to soils. It affects soil permeability and causes a loss of structural stability, so frequent long-term use can harm your garden, unless you are careful to spread gray water from laundry over a large area.
alkalinity
Laundry detergents are also very alkaline, meaning they have a high pH. A pH above 10 helps to dissolve organic dirt such as grease, oils and food waste. For reference, a pH of 7 is considered neutral, but for example, a highly caustic oven cleaner has a pH close to 12.5.
Most biological systems prefer a pH between 6 and 9, and graywater with a high pH can harm many plants and soil organisms.
We take into account the total load of troublesome chemicals that will build up in your garden over time, not just their concentration when you first put them in. The larger the irrigation area (minimum recommended area is 150-200 m2), the more the chemical load will spread.
The potential impact is highly dose-dependent. Try to reduce the amount of detergent you use, as long as the reduced amount still leaves your clothes clean enough.
Other considerations
The use of gray water in your area may be subject to restrictions or regulations from the water company, city council, or state and federal health and environmental protection agencies. For more information, contact a plumber specialized in the use of gray water and the competent authorities.
If you’re looking to install a gray water pretreatment system, do all of the above, plus check with your wastewater disposal authority if you plan on rerouting all or a significant portion of your used water.
