As a prepper busy stockpiling all the emergency essentials as possible, usually on a shoestring of a budget, wondering where your household’s wastewater goes after it swirls down the drain could not be further from your thoughts. But just maybe that waste or gray water is worth some consideration as a resource that would make full use of precious water supplies and save you money at the same time.
What is Gray Water
Gray water is any water that comes from sinks, showers, washing machines as opposed to what is termed as “black water” which is water that comes in contact with feces including toilet water and what is used to clean diapers. Black water has to be kept connected to sewage lines or septic tanks. Okay, so now that the gross part is accounted for, what can household gray water be used for? Irrigation is the primary use that motivates people to implement these systems. Irrigating with gray water saves money as you will be reusing what has already come through the tap which also helps conserve water in those areas experiencing their own shortages from reduced rainfall or long-run droughts.
How safe is gray water?
First and foremost, this is not water you can drink. It is waste water from your home associated with cleaning. What you use to clean is dissolved in the gray water. This is the point when you should be looking closer at what you use around your home for cleaning countertops and what’s in the soap you use on your hands, the shower and your clothes. Today’s cleansers, detergents, and hand soaps are none too friendly for plants. Bleach, dyes, salts, soaps with ingredients that leave you tongue-tied and products with borax are toxic to plants. Many laundry detergents are sodium-based, as well. Sodium will keep seeds from sprouting and ruin the structure of clay soils. Consider switching to products with more natural or biodegradable ingredients. Choose phosphate-based detergents as phosphorous is one those essential nutrients for growing plants.
So? Is it safe? Yes, gray water is safe to use watering your lawn, ornamental plants, fruit trees, your vegetable garden, yes. But there is a caveat. Because gray water may well contain bacteria do not use it directly on fruits or vegetables that will be eaten raw (apples, plums, turnips, onions for salads, etc). You can water fruit trees with it but don’t spray or water from the tops of plants.
What does a system look like?
Gray water does tend to have dirt, hair and grease so some filtration may be desired, although you can send it straight out to a storage tank or pipe it out to where irrigation is needed. Including a physical filter, a screen for example, to collect some of the grime is advisable. Residential gray water systems generally involve redirecting water from sinks, showers and washing machines into a reserve tank where the water will then be used for watering.
Another type of system involves a constructed wetland. This design incorporates natural filtration of the waste water exiting the house. The water is piped out into a designated area where reed type vegetation is planted in gravel beds, set usually at an incline. The water is filtered through the soil and drains down to a storage tank where the excess is collected for further irrigation use. This system is scalable, determined by the volume of gray water output and the space available. Some people have scaled these systems down to a size workable in apartments using planter boxes for their filtration. Others, with land to use, have constructed full gray water streams running through various levels of filtration zones, landscaped with vegetation and ponds.
Be aware though…
Gray water use can be touch and go depending on where you live. Some states and localities have embraced it while others have outright banned or regulated it to death (having confused gray water with black water) while still others simply haven’t addressed its use and have no standards to refer to. The best way to determine what, if any rules apply to using it around your residence is to check with the local department of public health. For those regions that do allow gray water for irrigation, their standards vary significantly.
- Some, like Arizona and Texas, do require permits if a daily discharge is below 400 gallons.
- California, New Mexico only ask that your system meets certain standards.
- Hawaii, Utah, Idaho, Nevada require design and permit approval.
- All require gray water not to be used or located where it may enter run-off to waterways, including rivers, lakes, and coastal waters.
- Watering is only permitted for drip or flood irrigation. No over the top or spray application because of inhalation dangers and transmission to other properties.
Wow, all these rules but what are the benefits?
- With up to 40% of household water use going down the drain as waste water, repurposing gray water for irrigation will reduce your water bill drastically.
- It reduces the volume of wastewater requiring treatment at public sewage facilities which in turn will reduce costs.
- Reduces strain on your septic tank.
- Reduces the drain on natural aquifers often already under strain from overuse.
- Increases awareness of our personal water usage and encourages the use of nontoxic products.