This post may contain affiliate links. If you make a purchase, I'll earn a small fee at no extra cost to you.*
Water is widely understood to be one of the greatest survival needs. Most survival teachers state that you need one gallon of water per person, per day for drinking and cooking. Unfortunately, many have taken that to mean you need one gallon of water per person, per day to survive.
This is a mistake. We use water for a wide range of things, not just drinking and cooking. Many of those are necessary for survival as well, especially long-term survival.
If all we’re talking about is a short-term disaster, you can get by with one gallon per person, per day. But preparing to survive only a short-term situation isn’t wise. There are many events that could lead to a long-term survival scenario. For those, you need to consider other uses for water.
Specifically, the highest additional priorities for water are cleaning and growing plants. I’m not talking about the lawn in front of your house or your flower garden; I’m talking about plants which you are growing to eat–a vegetable garden. You don’t need purified water for that. In addition, keeping your home clean is necessary to help control sickness and disease.
In a long-term survival scenario, you’ll actually use a lot more water for cleaning and watering your garden than for drinking and cooking. So water management should be a major part of anybody’s long-term survival plan.
What Is Grey Water and How Does It Fit In?
One of the best ways to manage water use is to reuse it. In reality, there are few uses of water that require it to be purified. We only need purified water for drinking and cooking. Everything else can be done with either unpurified water–such as you would get out of a pond–or water that has already been used.
Used water can be broken down into two separate categories:
- Black Water – This is sewage from the toilet. It can’t be used for anything else, but must go into a septic tank or sewage system.
- Grey Water – This is water that has been used for cleaning. While it isn’t clean enough for drinking, it can be used for other purposes.
The vast majority of the water we use in our homes actually goes down the drain as grey water, not black water. This means we’re essentially wasting that water. In a survival situation, where water is limited, we can’t afford to allow any water to go to waste.
What Can We Do With This Grey Water?
There are a myriad of ways in which grey water can be used. If you go back in American history, families bathed once a week, especially on the frontier. Of course, that was when they were drawing water from a well with a bucket and heating it on the stove; so filling a tub for bathing was a big job.
Since filling that tub took so much time and effort, everyone used the same bath water, starting from the youngest in the family and working their way to the oldest.
In a survival situation, where water is valuable, you will want to develop strategies similar to this. While water used for cleaning can only be used so much, most of the time we end up throwing out water that has not been used as effectively as it could be, especially bath water and water used for washing clothes.
Using that water to wash additional things, such as additional family members, your clothes, your dishes and your kitchen can help it go farther. Then, once you’ve washed everything you can, the water can be poured into your garden rather than down the drain. That way your plants can benefit from it as well.
Many people have expressed concern to me about using soapy water for their vegetable gardens, but I have had the water from my kitchen sink and my washing machine supplying water to my vegetable garden for quite some time. It has not affected my plants in any negative way, including the taste of the vegetables.
One last use for this water, if you can’t find anything else to do with it, is use it to flush your toilets. Water that goes down the toilet can’t be used for anything else, and it really doesn’t need to be clean. Simply pour a bucket of grey water into the toilet bowl to flush it, rather than using the lever to flush using the water in the tank.
This is actually rather common in third-world and emerging countries, where their toilets may not even have a tank. All you’re doing is replacing the tank and flush mechanism with the simple expedient of using a bucket. It works exactly the same.
Making it Possible to Use Grey Water
The biggest problem most of us have with reusing grey water is that our homes are not designed for it. Every bit of water we use is flushed down drains, either into septic tanks or into city sewer systems. This is wasteful, both on an everyday basis and especially in a survival situation.
Ideally, you would want your grey water to empty into a tank where it can be collected for use. However, this requires a major re-plumbing of your home, which might be against your local building code. However, there are some things you can do yourself, or with the help of your local plumber, which are fairly easy and make it possible to reuse your grey water.
Let me say that this is easier if you have a two-story home. As drain lines are gravity fed, you can readily divert them from an upper story much easier than you can divert them from the ground floor. However, it is still possible to use some of the grey water from ground floor rooms.
The key is locating where the water pipes are. This is easier than you might expect. Simply look at the drains for things like your kitchen sink, bathtubs and your clothes washer. Those will go down inside the walls to the home’s central drain point. In many cases, those drain pipes will be in exterior walls. That’s ideal for what you want to do.
With any drain pipe located in an exterior wall, all you need to do is cut a hole in the outside of the wall, cut the pipe and install an elbow. Then you can attach either an additional pipe or flexible tubing to this elbow and have it lead to your vegetable garden or to an outside grey water tank. I have done this with the water from both my washing machine and my kitchen sink and am using it for my garden.
Water from bathtubs can be reused directly while you are bathing. Simply put your dirty clothes in the bottom of the tub with some laundry detergent, and walk on the clothes while you bathe. As you “stomp the grapes” as if you were making wine, you will wash those clothes. Then, after that, the water can be left in the tub and used to flush toilets. All you need to do is place a bucket in the bathroom.
Want to prep but not sure where to begin? Sign Up for Our Newsletter and get your FREE One Year Urban Survival Plan!
All Grey water can be purified by distillation. A simple way is to build an above ground solar still, another although resource critical is to build a physical filtration system with a series of gravel/sand/charcoal media and then a final still for heat distillation. A fact that the mass media hides from us constantly is that H2O is forever, it is self refreshing through evaporation, the more of it that we run through our current sewerage treatment facilities the less the load on the treatment system. understanding dilution, evaporation, and condensation is the key to water recycling in a TEOTWAWKI situation.
(btw in the “olden days” it was the eldest who bathed first, and the youngest last, watch out for those revisionist history books)
Is there anyway to purify this kind of water?
All types of water can be purified using a solar water distiller. However, it does take time depending on the efficiency of the distiller and the intensity and availability to sunlight.
Also a water distiller can be built to be heated by fire. In a case where you are using fire the heat the living area during the cold season, this would be a very smart use of heat that otherwise simply go out the vent stack. This would however require a fire distiller to be built in a manner to could make good use of the heat.
I have a homestead where we redirect all of our laundry, and bath water to grey water. This keeps it out of the septic system. We were going to use the grey water for gardening. The problem, however, is salt. Soaps are very salt-based. A little isn’t a big deal, but we were worried about salt buildup in the soil. It may not be a problem, but my wife is a master gardener and she says we aren’t doing it.
However, grey water would be great for flushing the toilet and even some general cleaning. If I was going to direct it into a container – like a 55 gallon drum – then I would probably put the output spigot about 1/4 of the way up from the bottom. You want to take water from the “middle” of the water column. Heavy stuff will settle, lighter stuff will float. The middle is the cleanest.
However, how many baths and how much will you use the washing machine in a SHTF situation? We do 3 loads of laundry and take 2 showers a day regularly, but if we are in a water shortage I would guess that we won’t generate much grey water.
I think rainwater collection is way more viable in a SHTF situation than grey water. Rain water is cleaner and the rain will still fall (probably). An average roof will generate 1/2 gallon of water per square foot from 1″ of rainfall. A 1200 square foot house can generate 600 gallons of water from 1″ of rain. It’s best to have two different collection systems. Once one is full you purify it and start collecting in the 2nd. Then switch back and forth.
My bug out site, which I go to to farm, uses my black water through a digester. After methane extraction, the waste goes onto my compost pile. Post digester, the bacteria is mostly dead. The moisture and nutrients are rein fused into my garden.
what about the toxic chemicals in the dish/ laundry soaps like dawn are they not going to kill the garden?
Soapy water has been used as a wonderful insecticide for gardens for at leat the last 65 years!
My only previous learning on the subject of grey water came from Burning Man and that wasn’t about reuse, but leaving not trace. Great thoughts on reusing excess water instead of running it down the drain.