Domestic Water

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What is It?

This is fundamentally about our stewardship of the water in the natural water system, which is vital to our sustainability. Today, by code, So the elements of this are:

  • Toilet (4)
  • Sinks (3)
  • Shower (1)
  • Dishwasher (?)

  • A brief description of what it is.
  • If it is part of a system-level pattern put a link to it in here.
  • Also known as:

Why is it Important?

Describe how it:

  • strengthen our understanding and relationship with water
  • helps restore the planet's natural water system and quality of water for future generations
  • reduces the usage and associated costs of water from the public water system
  • creates One Earth patterns for water that others can use

When to Use It?

  • List the important considerations when to use this pattern.
  • When would it be sustainable?
  • When would it not be sustainable?

Green Garage Use of Domestic Water System

Sustainability Goals

  • Return 100% of the rainfall to the ground table for up to a 10 year storm
  • Clean the rain water before it re-enters the water table
  • Harvest rain water adequate to meet the watering needs of plants and trees on the Green Garage site.
  • Develop connections between people and the natural water cycle.
  • Use zero city supplied water for outside purposes

  • The specific goals we're trying to achieve. This should be the performance outcomes.
  • It doesn't describe how...just the outcomes.


  • Minimize the Demand for Water
    • Reduce the flow or usage of water
  • Harvested Water Strategy
    • Harvest water for the plants in reused barrels and storage tanks
    • Store the harvested water close to where it will be used
    • Begin with a moderate amount of water stored and increase as the need arises
  • Peculation Field
    • Create a peculation field in the parking lot and front of the building where the demand for water is highest due to the sun and plants.
    • Convert the truckwell to a retention underground retention pond.???
  • Building drainage
    • Move as much to the front as possible...this is where the sun is
    • Leave the storm drainage as a backup capacity, especially that in the truck well.

Conceptual Design

Usage Volume/Day Source Outflow
Toilets / Urinals
  • Quantity: 3 - Toilets; 1 - Urinal
  • 90 gal/day (25p x 3 flushes x 1.2g/f)
  • Dual Flush (0.9g / 1.6g)
  • Waterless urinal

Rainwater Storage Well

City Sewer

  • Quantity: 1 - Shower
  • 50 gal/day (5p x 10 g/s)
  • Low flow (2.5 gal / min)
  • Japanese shower style seat
  • Heated in floor?

City water system

City sewer system (gray water?)

  • Quantity: 3 - Sinks
  • 75 gal/day (25 p x 3g)
  • Flow controlled - auto shut off
  • Can be solar powered?

City Water System

City Sewer System (gray water?)

  • Quantity: 1? - Dishwasher
  • 8 gal/day (2 times x 4 gal/run)
  • high efficiency
  • Can be solar powered?

City Water System

City Sewer System (gray water?)

Emergency Watering
  • Quantity: ??
  • gal/day

City Water System


  • 223 gal/day

133 gal/day City Water System 90 gal/day Rain water

233 gal/day City Sewer System

Source of water for these:

  • Toilets - rainwater
  • Sinks - public city water
  • Shower - public city water
  • Dishwasher (?)- public city water

  • Storage
    • 500 gallon tank on the side of the building near the truck well at 12 feet high. It will act at the water for the front of the building. The pressure will be approximately 20 psi (normal city water supply is in the 40 - 60psi range)
    • 2,500 gallon tank underground in the backyard near the alley (SE corner.) The this would be a community rain water well. It would also be used to water the alley plants.
    • 10 - 55 gallon rain water barrels. Most on the roof where the water would be needed most. Some in back near the compost bin for cleaning and watering plants.

  • Describe how we plan to achieve these goals
  • Explain why we chose this specific strategy and design (our rationale)
  • Include pictures, drawings or videos(flickr)
Supporting science:
  • Google Water Analysis spreadsheets
  • One Green Generation says: In 2006, Waterwise studied the amount of water used in hand washing versus machine washing. According to their website, “Waterwise is a UK NGO focused on decreasing water consumption in the UK by 2010 and building the evidence base for large scale water efficiency. We are the leading authority on water efficiency in the UK.”

I could not find the study online, but according to several places it was quoted, the study found the average dishwasher uses between 12 and 16 litres (3-4.25 gallons) of water, while washing dishes by hand uses as much as 63 litres (16.5 gallons).

Proposed Materials / Suppliers

  • Identify (via links and short description) the materials and suppliers we propose to use.

Development Story

The Domestic Water - Development Story page contains many images and videos documenting the process used at the Green Garage to design, build and operate our ?? system.

Related Internal Links

  • Help people find other related Green Garage pages that may help them. Keep it tight.


To Do's

  • Figure our gray water


Greywater, What is It?

Any wastewater generated from non-industrial sources such as dishwashing, hand washing, bathing, and laundry is referred to as greywater. The wastewater that is generated by the flushing of toilets is considered blackwater. The distinction between greywater and blackwater is the concentration of toxic and biological contaminants, such as toxic chemicals and feces. Wastewater from kitchen sinks that contain large amounts of solid particles, wastewater containing high levels of toxic substances from household cleaning products, or wastewater from laundered diapers, can also be considered as blackwater. Greywater constitutes 50 to 80% of residential wastewater.

The conventional method of disposing greywater is to combine it with blackwater, and then direct it to septic tanks or sewers. This approach can result in system overloading. An additional shortcoming of this process is the contamination of the natural waters with poorly treated discharge. The later is especially true when sewage treatment facilities are burdened with storm sewer runoff during periods of heavy rain.


There are many re-uses for greywater. Diverting greywater for irrigation of landscaping and gardens are two possibilities, and with proper filtration and purification, the water can be re-used to flush toilets and for laundry purposes. There are claims that with high amounts of purification and decontamination of greywater, the resulting water can be potable, hence fit for human consumption. There are Do It Yourself (DIY) approaches and commercially available systems intended to treat greywater. Books and the Internet are good sources for information. A good system will deliver the best results in the proper context, with minimal maintenance and complexity. The ideal system should also have an overall positive environmental benefit.


The benefits of greywater re-use can be both ecological and economical. Foremost, there is a lowered demand for water extracted from natural sources. Because greywater can be used for irrigation, the small particles of food from kitchen sources also provide nutrients to the soil. Greywater returned to the earth is also effectively purified by the layers of soil as it permeates downward where it will replenish the water table. Returning greywater to the earth reduces the volume of water that will need to be treated by septic and sewage treatment plant systems, and the associated energy demands. The reduced reliance of city water for landscape and garden irrigation will also provide a cost savings to the occupants of the residence. A further benefit is choosing ecologically friendly cleaning and laundry products, which will increase demand, possibly resulting in lower costs and increased awareness of the impact of toxic cleaning products.


The greywater water can be sent to where it is needed by gravity, or by means of a pump. Precautions should be taken when the greywater is transported by a pump, as particulates and hair can foul the pump mechanism, prematurely ending the life of the pump.

Testing has shown that untreated greywater is considered to be a potential health risk and source of pollution, as the same types of micro organisms can be found as those which are present in blackwater (sewage), although at lower levels of concentration. The amount of risk of the spreading of disease becomes greater as the number of dwellings that share greywater re-use increases. Because of this concern, care should be taken not to consume unpurified greywater, or use it to irrigate any vegetables that may be consumed, especially un-cooked (raw). The best practice is to use greywater as irrigation of the soil surrounding vegetables and trees. This practice also minimizes risks of the spreading of micro organisms in an aerosol form when spraying and other forms of above ground distribution are used. As toxic chemicals can contaminate the soil, the proper choice of home cleaning products, laundry detergent, and other additives should be exercised. --Temp2009 15:13, 7 May 2009 (UTC)