Recycling Water

The historic draught of 2007-2008 opened many people’s eyes to the very real prospect of a fresh water shortage. Until then, most modern-day Americans took it for granted that clean, fresh water was always just a twist of the faucet away; forever available in any quantity we desire. During that time period, many residents, especially in the Southeast, learned the reality that fresh water is not an inexhaustible resource. Since then, more people are looking at fresh water in a new way.

Some people, while not in drought areas, want to decrease their dependence upon a water utility. In both cases collecting and using rain water and some waste water can help them achieve their goals. By recycling the water they have access to they can maximize their use of that water. But this must be done carefully to prevent health and legal problems.

Two types of water can be collected for use: rain water and grey water.

Legal Ramifications of Recycling Water

In some areas, especially in drought plagued areas, it has actually been made illegal to collect grey water and even rain water. Doing so will label you as a hoarder and you can face stiff fines for theft of a public utility. The government can’t claim ownership of the rain, but they can claim rights to ground water. By preventing rain from becoming ground water – even temporarily – they can claim to have been stolen from and will sue.

If you are on a public water utility, the utility claims ownership of the water they sold you. By diverting the grey water (non-sewage waste water) for additional use you are (according to them) receiving additional value for which you have not paid.

These are issues only in areas where drought has become a way of life and water rights are particularly precious. Most areas of our country are not so over-possessive of water rights. If your home has a private water well, the issue becomes even less of a problem. Still, before investing time and money into an elaborate system for recycling water, check your local ordinances to be sure you won’t bring the law down on you for what you see as a perfectly reasonable use of rain or grey water.

Collecting and Using Rain Water

Courtesy Mother Earth News

Rain water collection can be as simple as an ordinary barrel or trash can stuck under a downspout from which you dip water for watering your garden or flowers. Upgraded versions include a spigot for a hose and an overflow pipe. High capacity versions add additional barrels with cross-over pipes and elevate the barrels for additional oomph to the water flow. Large, whole house systems use huge tanks to store water to be used for washing machine, flushing toilets, showering, and doing dishes.

Installing a hybrid whole house rain water system means having two sets of water supply lines in your home: one for well water or utility water that goes to sinks for direct consumption or food prep and another set of pipes to supply rain water to non-consumption fixtures and appliances. This can be a difficult remodel in an existing home, but quite easy to implement if you are considering building a new home.


Elaborate systems for storing potable (drinking) water involve multiple, large tanks with a timed diverter valve to purge debris from the roof-top collection stream at the beginning of a rain, filtration systems and chemical treatment to prevent microorganisms and algae from growing in the water tanks that may cause you and your family harm.

In this case, one set of plumbing pipes can be used in the home and well or public utility water – available as emergency back-up – would be brought in through a shut-off valve to a supply tank. That makes this system a better choice for existing homes.

One note: if you are planning a new home with an incorporated rain water collection system, plan to use metal or clay tile roofing and avoid the pollutants that can leech out of asbestos shingle roofing.

Grey Water Collection Systems

Grey water is the term given to household or commercial waste water that contains no sewage (human bodily waste) or concentrations of chemicals. Water produced by doing laundry, showering, bathing, washing hands, washing dishes, brushing your teeth, etcetera produce grey water. The name comes from the cloudy gray appearance of such used water. For most households’, around 80% of the waste water they route to a septic system or city sewer system is grey water.

Of What Use Is Grey water?

Grey water is not potable water; it may not be used for drinking or cooking and should not be used for bathing or washing dishes or laundry.  But, it can be used to flush toilets, irrigate flower beds, trees and some parts of the garden, and to establish and maintain a wetland zone. The ability to use grey water for flower and garden irrigation is particularly attractive to those living in drought zones where water restrictions and rationing are likely.

The Down-Side of Grey water Use

The major objection to the re-use of grey water is that it can contain pathogens and nutrients that if stored or used improperly could constitute a health hazard. For example, if water from the kitchen sink is diverted to a toilet tank, bits of food in the water could collect in the tank, spoil and create the potential for bacterial infection.

A few municipalities claim that they actually need all the household wastewater coming in and being processed to keep reservoir levels up – such as Lake Mead in Nevada. If users were diverting 70% of the water they consume (drawn from the lake) from the sewer lines and returning it directly to ground water, the reservoir level would be difficult to maintain in dry seasons.

Government Regulation of Grey water

State, County and City governments may choose which plumbing standards they wish to apply to their residents. Currently states that adopt the International Plumbing Code, allow grey water to be used for sub surface irrigation and for toilet flushing, and in states that adopt the Uniform Plumbing Code, it can be used in underground disposal fields that are akin to shallow sewage disposal fields. But, these “disposal fields” are covered by all the same restrictions and permitting regulations as a septic field. Often these regulations are used to discourage homeowners from installing grey water irrigation by tying them up in red tape and applying high permit fees.

How to Install a Grey Water Recovery System

In existing homes installing a fully functional grey water recovery system is complicated and expensive due to the extensive amount of re-plumbing needed and the installation of tanks, filters, and pumps.

Simplified versions are, however, very easy. One example of the simplest forms is to connect the discharge hose of your washing machine to a line that leads to a series of buried soaker hoses under your lawn. You would need to install a relief valve and diverter so that, should the irrigation lines fill to capacity while the washer is pumping out, the excess water would be diverted into the normal washer discharge pipe of your plumbing for disposal. This sketch offers another system. Direct the discharge from household sinks into buried lines that take the water to flower beds, trees and/or garden.


  • No filter
  • No pump
  • No surge tank
  • Uses very little pipe
  • Little or no maintenance
  • Low economic cost
  • Low ecological cost
  • Anyone can build it
  • Failure rate is low
  • Lasts forever

When installing drain lines to route grey water for irrigation purposes, avoid using perforated plastic lines such as is used for septic field lines unless your grey water has been run through a sand filter or a septic tank like separator. Grey water – especially water from a washing machine and the kitchen sink – has a high amount of “stuff” in it that will quickly clog the holes in perforated pipe. Better solutions are old fashioned clay tile or this garden drain product that has one whole face as a fabric filter, designed to let water in freely yet keep dirt out, it works the other way around, as well.

Some home owners are installing home-made versions of commercially available grey water toilets that combine a hand washing sink with the toilet tank to simply and automatically re-use hand wash water. This is a simple and effective solution that requires no modifications to the household plumbing.

A full blown grey water recovery system requires a tank for filtration and separation of solid food bits as well as treating the water to kill microorganisms. Most areas strictly forbid the storage of grey water for longer than 24 hours because after this time the microbial activity in the grey water uses up the oxygen in the water and it becomes septic. At this point it must be disposed of as sewage. These fully engineered systems include an intelligent system for flushing the storage tank periodically if it is not cycled naturally. There will also be filters to clean periodically.

Some systems provide such efficient filtration and disinfecting (similar to swimming pool filters) that the water can be returned to potable or near potable condition for re-use within the home. Such a system is being used by the Mars Desert Research Station and is being considered for use in future manned Mars missions. But those systems are very expensive and outside the scope of this article. If you’re interested in these visit this [Grey Water Harvesting System] web site.

Considerations for Grey Water Irrigation Systems

There are a few things to consider before attempting installation of a grey water irrigation system:

Grey water recovery systems are not a one-size-fits-all solution. There are many variables to consider, and improper design will probably reduce the effectiveness of the system so much that the net advantage is negligible. A few mistakes can create health hazards – although there have not been any grey water connected health problems reported to date. Do some homework to avoid making the common mistakes of grey water recovery system installation.


Rain water collection systems can be simple and efficient to install and reduce your dependence on utility water for things like irrigating gardens and flowers. More elaborate systems can provide household use as well.

Grey water recovery systems can offer relief to anyone in a water-shortage area. Since that situation is likely to affect more and more of us, this is an issue those looking at new home construction – especially in the Southeast – should consider carefully, and those with existing homes should look at limited retrofits to reuse as much household grey water as is practical.

Getting good solid information on what works well in your area, what is legal and what is not, and what your projected benefit will be before you start is only prudent.

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