WHAT IS A GREYWATER SYSTEM?

This a Pretty Big Post so I Broke it Down into six sections with a navigational  Table of Contents so that you can easily jump to what you are looking for.

Before We Get Started...

My goal is to give you simple clear instructions to implementing a working greywater system for your home as quickly as possible. 

However, no matter how hard a writer of a 'How To' article tries to cover every detail of a DYI project sometimes end users will have circumstances that don't match the instructions being given.  In these cases acceptations to their circumstances need to be made as it is of course impossible for the author to know every acceptation out there.

Whenever you are unsure about any step provided and before you take any action  please contact a local professional to assist you in installing a safe and reliable system.

GREYWATER BASICS

What Exactly Are Greywater Systems?

In a nutshell, a typical residential greywater system collects greywater from one or several sources in your home (i.e. washing machine, utility sink, bathroom sink/shower) and delivers via distribution/irrigation piping to your landscaping.

Benefits of Greywater

Why Do We Need Greywater Systems?

Sooner or later we will run out of available drinking water if the non-stop overuse of fresh water for non-essential tasks is continued.

Our planet’s water needs are rising rapidly causing shortages of potable (drinkable) water and  increasing the pressure to find alternative water supplies.

The problem is found in almost every country today and more than 1.2 billion people do not have the access to clean and fresh drinking water and this number is growing year after year.

Greywater can replace fresh water that is used for non-essential tasks like washing autos, spraying off driveways and irrigating status lawns.

Unlike a rainwater harvesting, which obviously requires rainfall, a greywater system never runs short of water and is a predictable safe water source. Reuse of it will helps preserve fresh water sources of water for present and future use.

The more of fresh water you use, the more greywater you generate.

What's Legal in Your State?

There are risks involved in the use of greywater, so a system needs to be installed and managed per code.

There are some municipalities that do not like greywater reuse because it reduces the amount of water that is returned to them for treatment and re-use.  If you install your system incorrectly it could be in violation of your local codes and an inspector could make you tear  your entire installation out.

Greywater codes vary depending on where you live. In some states the code is very progressive and unfortunately in other states there still is a lot of work to be done.  If you live in a state that has not sufficiently addressed greywater codes, please contact your legislators with your concerns.

To help you quickly access your states information on codes please use the interactive map I have provided below.

Simply click on your region and then click on your states name which will take you to the most current code information I could find for your state.  

The states are divided into two groups; States without formal greywater regulations and States allowing greywater reuse.  I have indicated after each states name which group your state falls into.

Types of Codes

As you research your states greywater codes use the two following definitions to help guide your understanding of what kind of code structure your state has.

Performance-based codes: (also known as outcome-based) define the requirements for greywater systems.  Those systems which meet the requirements are legal and all others are illegal.  Performance-based codes are simple and typically do not require permits or inspections and their associated fees.  However, sufficient legal leverage is given for the city to enforce compliance.  

Prescriptive Codes: Specifies exactly a certain standard of how each component of a greywater system is to be constructed and operated.

MANAGING GREYWATER

Main Objectives

Rural Areas

It depends on the situation but most locations in a rural setting do not produce greywater in high concentrations. People living in the country have septic tanks or leach fields and use wells and/or have access to other natural sources of water. For most living rurally greywater management usually
holds little interest.

Urban Areas

Since populations are higher in urban centers, we can expect greywater to be produced at higher concentration as well as the accompanying pollutants.

With so many residences and buildings per square foot there is limited space for greywater systems to be installed.  Implementation of urban greywater systems requires innovative consideration as currently the demand for greywater within this environment is lower than its production.

Indoor Uses

In the built environment the two major consumers of water are toilets and washing machines.  Before using greywater as source water for these purposes proper filtration and disinfection is required.

Outdoor Uses

Industrial/Commercial: After greywater has been properly treated it has multiple uses at the Industrial/Commercial levels. Properly treated greywater has no foul odor, so it can be used at car washing centers, commercial pressure cleaners and high-pressure water cutters.

Landscape features, gardening, and irrigating fields: Greywater restores nutrients that are beneficial for plants. Avoid concentrating greywater in one area of the garden, this will result in increased salt content in the soil and can adversely affect the health of your plants.

Plants

Some plants do well with greywater, but you will need to research your own plants.  Here is a quick list of common plants that do well with greywater:

Currant, raspberry, blackberry, gooseberry, filberts, rhubarb, elderberry, passion fruit, kiwi, hops, and grapes. Blueberries, Yaupon, Smooth Sumac, Ceanothus herbaceous, Yucca glauca, Stretch berry, Redroot, Atlantic ninebark, Fragrant sumac, Scarlet globemallow, Dwarf palmetto, soapweed yucca

Do and Don’t

• Do wash your hands properly after handling greywater.
• Do system maintenance/repairs asap.
• Do use the correct kind of soaps. 
• Do not use greywater to water vegetables that are being eaten raw.
• Do not let animals or humans drink untreated greywater.
• Do not let greywater make direct contact with the plants.
• Do not use hot greywater for irrigating purposes, it may kill the various
  organisms present in the soil that are beneficial to plants.
• Do not use greywater for indoor purposes without treating it properly

Give Back

As more greywater is diverted for reuse municipal sewer systems will see an increase in blocked sewer lines.  Greywater plays a big part of turning solids into liquid so their easier to pump, therefore it is a good idea to occasionally divert some of your greywater back to the municipal system.

Mixed not Shaken

A question often asked is can rainwater be mixed with rainwater and the answer is yes and no.

Yes, if you have treated your greywater and you intend to irrigate with it. Collected rainwater should be treated like gold, to avoid cross contamination it should be mixed with greywater in a separate barrel/cistern from the rainwater harvesting system.

No, if you have untreated greywater. 

Mixing, treating and reuse of rainwater and greywater is best left for an pre-engineered skid.

Odor

To avoid odor emitting from your greywater system simply use the water within a 24-hour period. 

A greywater system should be set up so that it is delivered from its source to its destination immediately

IMPORTANT: Flush a system at least one per day to mitigate odor and pathogen/bacteria growth.

The Environment and Greywater

This is extremely important topic.  If precautions are not taken you could be putting greywater on your plants that has a high level of sulphates derived from using the wrong kind of soaps.

Extended sulphate build-up will deteriorate the quality of your soil. 

Soaps

Only use low sodium soaps.

No bleach.

pH neutral soaps

COMPOSTION OF GREYWATER

What's in Greywater?

In the built environment, occupant water use behaviors are the key contributors in greywater composition. The various components found in grey water are:

• Pathogens
• Various metals and pollutants
• Various Nutrients

Let’s give each of these a closer look:

Pathogens

The World Health Organization (WHO) and the United States Environmental Protection Agency (USEPA), the US Agency for International Development (USAID), Mexico and Germany all have set standard guidelines for grey water quality and handling.

However, the International Development (USAID) USEPA and USAID have set extremely strict guidelines for treated greywater reuse. Unrestricted irrigation of crops meant for human consumption is to have no detectable fecal coliform bacteria present for every 100 mL of water. For commercial irrigation and use on fodder crops the allowable limit is < 200 cfu/100 mL.

Metals & Pollutants

Various metals found in grey water are, but not limited to:

• Mercury
• Lead
• Nickel
• Cadmium

Though the amount of these metals and toxic pollutants found in grey water is generally low, they may be found in higher concentrations dependent upon location and use.

Human behavior is the main catalyst in the contribution of pollutants into grey water so good choices need to be made like using environmentally friendly materials or looking for ways to eliminate harmful constituents. Simple behavior changes can have dramatic effects on lowering or eliminating metals and pollutants making it easier to treat and re-use grey water.

Nutrients

The use of grey water nutrients depends on which nutrients and in what quantity they are present, i.e. nutrients like phosphorous can affect the water quality.

It may seem like a promising idea to have nutrients in grey water, but it depends on which nutrients and in what quantity they are present i.e. nutrients like phosphorous can affect the quality of the water.

The main source of phosphorous in grey water is washing detergent, therefore detergent use within households can contribute a considerable amount of phosphorous into the water.

As a result, many countries have banned the use of detergents containing phosphorous because elevated levels of phosphorus will cause algae to grow faster and interfere with the balance of the ecosystem resulting in a decrease in water quality, habitat and food resources. 

Design considerations

Greywater is predictable and easy to calculate the amount of available water for re-use. This is an important first step in understanding how much potential water is available for re-use.

So first you'll need to calculate  annually your potential greywater capture is...

How Much Grey Water Do You Produce?

Mesh Bag Filter

Greywater is first passed through a coarse mesh filter bag. This removes any large particles such as lint and hair immediately. The greywater is then passed through a much finer filter to remove the small particles.

Slow Sand Filter

A slow sand filter removes the smallest particles. A slow and constant flow of water through the filter described above leads to biological activity as the top layer of sand traps micro-organisms (e.g. bacteria). “bio-film builds up on top of the sand.”

Inline Filter

There are a plethora of commercial inline filters available on the market.  Inline filters are typically installed in more sophisticated systems but be can used in the typical residential system.  If you are unsure about what inline filter is right for your system I highly recommend that you discuss your options with a local professional before purchasing.

Installation

If you have all your parts and pieces assembled, it could take as little as one day or as long as a week for more complex systems.  On average though a simple system can be installed in a weekend.

There are preassembled greywater skids that you can order and have delivered to your site.  The skids come pre-engineered and ready to be connected to power and piping. This option is usually used in large residential, commercial, or industrial applications.  

Do You Need to Call a Professional?

This is contingent upon a couple of things:

Your competence level with DIY plumbing projects.

How accessible and the location of the connection points.

The type of system you install.  The shower bucket to landscape technique only requires your willing to shower with a bucket and the brute strength to carry it out to your yard.  Even the simple laundry to landscape system requires you to assemble pipe and fitting.  And of course, more complex systems should involve a plumber and even possibly an engineer.

Bottom line:  If you have any reservations about installing a system get a professional involved.  The cost of hiring a plumber will pay back ten-fold in peace of mind, reliability, and legality.

Cost

The cost of a greywater system varies from depending on your location and type of system you want to install and the volume of greywater to be processed.

There are preassembled greywater skids that you can order and delivered to your site.  The skids come pre-engineered and ready to be connected to power and piping. This option is usually used in large residential, commercial, or industrial applications and can be quite expensive.

I highly recommend you start small and design for expansion.  Smaller systems will cost less and require less maintenance.  If you need more capacity you can add it when necessary.

I don't like to give out vague cost estimates because some people will spend money to have only the newest and the best while others are content to hobble together the parts and pieces needed for almost nothing.  

None-the-less I'll give you a range:

Inexpensive/Small:  $75-100

Intermediate/Large: $100-$1,500

Complex: $1,500-10,000+

10 Basic Steps to Laying Out a Greywater System

TYPES OF SYSTEMS

Let's Be Honest

If you don't have a lot of experience with grey water and/or plumbing the less complicated and more affordable I can make the steps the more likely you are to take action.

Since my goal is to get you installing a grey water system as quickly and easily as possible, I am going to focus on the basics of each kind of system.  You can always expand or add to your system once you have a working system in place.  It’s harder to tweak a complicated system than it is to amend a simple one.  So, when selecting the type of system, you want to install, keep It simple.

If you have previously researched greywater systems, you most likely have discovered there are several different types of systems with differing options and details.

For the uninitiated it can be a little confusing as to what kind of system is right for them and what options are necessary or can be omitted.

I struggled with how to tackle this problem so that you can as quickly as possible get your greywater system up and working. 

What I landed was simplicity.  

Following are six of the most common  types of greywater systems:

The Simplest of Systems

The simplest type of greywater system is a bucket or dish basin, I know that it’s not very exciting, but it gets the job done. 

All you need to do is simply collect the water from your sink/shower and carry it out to your plants and trees.  As with all systems make sure to use environmentally friendly soaps (See section on soaps) and don’t overwater one particular spot in your yard.

A Surge Tank System

The next simplest system is using a surge tank.  Surge tanks can be added to other types of systems as well but can also be used as a stand alone system.

It’s pretty simple to build but may need a little tinkering to get working properly.  As you can see from the image below/above it works based on utilizing gravity to push the greywater out to your landscaping.  On the outlet side you can either run hard piping or a garden hose to dispute the water to your yard.

Some systems have a surge tank placed between the washing machine and the distribution piping, but it is not necessary for the system to work. In the Laundry-to-landscape diagram below you can see I did not add a surge tank to my system but instead designed it so the catchment area at the top of my sand filter has sufficient room to hold water from a full load of laundry. 

An example of a surge tank can bee seen in the diagram located below under System Type #5, Branched Gravity System.

Click on the image Above or on any system component Below to learn more.

Automatic Bypass (Freezing climate only) – Not Shown

For those of you living in climates that experience freezing you will want to install automatic bypass.

An automatic bypass is constructed of two wye type fittings that are joined at their horizontal connection points by a ball valve.  Two pipe runs of equal distance are installed at the wye fittings vertical connection points and run up to the maximum fill point of the tank. At the top of the vertical legs two 90-degree elbows are used to connect the two pipes.

This allows the water to rise up the 1^st vertical pipe and overflow into the 2^nd pipe if the line freezes with ice.  This prevents damaging the pump and flooding your laundry room.

Hose Service Connection (Not Shown)

This is a simple connection point where you can add a garden hose to blow out the line of debris to keep the pipes clear of obstructions.  The connection should be installed downstream of the backflow preventer.

Backflow Preventer (Not Shown)

As the name suggests a backflow device prevents the backflow of grey water into your system.  Without a backflow preventer you run the risk of greywater flowing back into your washer creating odor and possibly ruining your laundry.

Constructed Wetlands System:

I first learned the name of these systems as sludge monsters long before I knew they were called constructed wetlands.  I still often default to sludge monster.

The idea is simple, utilizing what mother nature gave us, hungry plants. The plants absorb nutrients and particles from greywater that they need.

The recommended constructed wetlands used in backyard systems is referred to as subsurface-flow or reedbed systems where the plants grow in gravel or soil.

Gravity Branched System

A branched drain system is another type of simple system that uses gravity to distribute greywater to it desired endpoint.  It’s based on sloping the distribution piping downward ¼” inch drop for every foot it travels horizontally.

Although this is a simple system in concept it can be difficult to install because of the need to keep the source point above the delivery points.  It also requires you to alter or tie into your existing plumbing which can make it a financially unattractive option.

Pumped System

A pumped system sounds exactly like what you think it does, it uses a pump(s) to distribute grey water to your landscaping.  It’s used when gravity cannot be sufficiently leveraged to do the job.  Like if you need to move greywater up a slope and/or long distances to its distribution points.

A typical system is constructed of an effluent pump mounted on the bottom of a 50-gallon plastic barrel. The barrels inlet is located at the top of the barrel and once sufficient water has filled the barrel it is then pumped out to the distribution lines.

NOTE: Pumped systems require regular consistence maintenance and cost to operate.

FYI.  For large scale greywater pumped systems like ones used in hospitals, universities & apartment complexes you can order skid mounted multi-pump, barrel, and filtration systems. If you have a greywater system of this size it will need to be designed and installed by licensed professionals