Water Conservation and Water Recycling

On-site Sewage System Using Subsurface Drip Irrigation Using Less Than 3,500 gallons per day

Description:

A type of wastewater system that is designed to treat wastewater while utilizing the water and nutrients available to irrigate and support the growth of plants.

A subsurface drip system is an efficient pressurized wastewater distribution system that can deliver small, precise doses of effluent to shallow subsurface dispersal fields.

Benefits:

• Uses all the wastewater from a building.

• Produces healthy, fast-growing plants.

• Gives you the ability to put water exactly where it's needed and keep paths and areas between plants dry. This reduces both waste and weeding.

• The amount of wastewater used during irrigation can be controlled precisely so that nearly all of it remains in the root zone where the plant can use it the most.

• Delivers equal amounts of water to plants over a wide area.

Notes:

To maximize wastewater recycling, consider using a subsurface drip system to handle all the "wastewater" from the building. By doing so, you can take the "waste" out of wastewater. These systems are designed to treat residential strength wastewater while utilizing the water and nutrients available to irrigate and support the growth of plants. By design, they maximize wastewater recycling.

To learn more about subsurface drip systems read the Recommended Standard and Guidance for . . .Subsurface Drip Systems.

Rules:

Chapter 246-272A WAC

Permits:

Issued by the local health jurisdiction

Greywater On-site Sewage System Using Less than 3,500 gallons per day

Description:

An on-site sewage system used in a building equipped with waterless toilets. This system must be designed as an approved on-site sewage system under Chapter 246-272A WAC. Under these rules, the system may be designed and used as a subsurface irrigation system.

Benefits:

Water conservation as part of a greywater on-site sewage system can be obtained by two processes:

1. Reduce the volume of water used (to transport wastes through piping), and
2. Recycle wastewater for subsurface irrigation of plants, shrubs, trees, and turf.

To learn more about greywater on-site sewage systems read the Recommended Standard and Guidance for . . . Water Conserving On-site Wastewater Treatment Systems.

Notes:

Because a greywater on-site sewage system is a permanent wastewater system, it must be designed to handle normal variations of wastewater strength year round and have a surge capacity to handle a variety of water use scenarios. To ensure public health and environmental protection, this system must be designed and maintained using the on-site sewage system rules.

Rules:

Chapter 246-272A WAC

Permits:

Issued by the local health jurisdiction

Greywater Reuse for Subsurface Irrigation

Description:

Greywater* is used only for subsurface irrigation applied at a rate to meet the water needs of the plants during the growing season.
*"Greywater" means domestic type flows from bathtubs, showers, bathroom sinks, washing machines, dishwashers, and kitchen or utility sinks. Greywater does not include flow from a toilet or urinal.

The building must be served by an approved wastewater system to use these rules.

Benefits:

A new rule, Chapter 246-274 WAC, provides building owners with simple, cost-effective options for reusing greywater for subsurface irrigation. It is intended to encourage water conservation while protecting public health and water quality.

Notes:

The state rule is effective as of July 31, 2011. Local health jurisdictions (LHJ) need to write local codes to allow this use. Check with your LHJ to find out if it is allowed where you live.

These systems are for seasonal use only, when plants are growing and need to be watered. The amount of water allowed is limited to what can be used by the plants, taking in account loss to evaporation. They are designed differently than on-site sewage systems. The permanent wastewater system must be designed to handle normal variations of wastewater strength year round and have a surge capacity to handle a variety of water use scenarios.

To learn more about Greywater reuse visit Department of Health's Greywater Reuse web page.

Rules:

Chapter 246-274 WAC

Permits:

Issued by the local health jurisdiction

Greywater recycling, rainwater collection, or other processes that include plumbing alterations are possible options for wastewater recycling and water conservation.

Description:

Recycling of any water, including greywater, inside of a building for flushing toilets and other nonpotable water uses is covered under the Washington State Plumbing Code.

Benefits:

When you think about it, flushing toilets with drinking water doesn't make sense. We spend a lot of money collecting and treating water so that it is drinkable and then we use it to flush the toilet? In some locations you may be allowed to have your home plumbed so that you can recycle wastewater from your washing machine, sinks, tub, and shower to flush your toilet.

Notes:

Check with the local building department to determine what is allowed. If you live in King County, read http://your.kingcounty.gov/dnrp/library/water-and-land/groundwater/liquid-assets-brochure/p8-doing-our-business.pdf and https://rainwise.seattle.gov/city/seattle/overview to learn more.

Rules:

Chapter 51-56-1600 WAC

Permits:

Issued by the local building or plumbing department.

Large On-site Sewage Systems (LOSS)

Description:

A LOSS is designed to convey, store, treat, and provide subsurface soil treatment and disposal of domestic sewage for a design flow of 3,500 to 100,000 gallons per day.

Benefits:

LOSS offer an alternative to centralized municipal sewage treatment plants and can serve from 10 to about 370 individual residences, or equivalent flows from schools and churches, campgrounds and recreation vehicle parks, resorts or state park sites, or smaller cities or towns. All on-site sewage systems (including LOSS) potentially provide groundwater recharge. When the loading rate is greater than the needs of the plants and evaporation, ground water recharge is possible. The primary other legal reuse application for LOSS is subsurface landscape irrigation. All other beneficial uses require a reclaimed water permit. The safest and most effective way to irrigate landscape plants with LOSS effluent is by using subsurface drip tubing for the distribution component of a LOSS.

Notes:

A LOSS that utilizes a properly designed subsurface drip system (see above) is a fabulous option for recycling wastewater. To maximize irrigation efficiency the system designer must consider environmental conditions including soil characteristics, plant types and local weather conditions.

Rules:

Chapter 246-272B WAC

Permits:

Issued by WA State Department of Health Large On-site Sewage Systems (LOSS) Program

Reclaimed Water is a water supply produced by treatment of municipal or domestic wastewater.

Description:

Reclaimed water is an important component of wise water management. Reclaimed water is derived from domestic wastewater and small amounts of industrial process water or stormwater.

Benefits:

Reclaimed water is used for a wide variety of beneficial uses such as surface irrigation, industrial process and cooling water, toilet flushing, dust control, construction activities, and many other uses of non-potable water supplies. It is also used as a resource to create, restore and enhance wetlands, recharge our groundwater supplies, and increase the flows in our rivers and streams.

Notes:

Reclaimed water is a hybrid program with elements from numerous federal and state regulations. These include water resource management, water supplies, urban and watershed planning, wastewater management, wetlands, groundwater and surface water protection, and public health and safety. It is important to realize that these requirements are established for different purposes.

Rules:

Chapter 90.46 RCW

Permits:

Issued by WA State Department of Ecology Reclaimed Water Program