Quite a few credits deal with something called Graywater and Blackwater. Graywater is defined by the UPC (uniform plumbing code) as untreated wastewater that has not come in contact with toilet waste. Examples are shower water, water from sinks, bathtubs, bathroom wash basins and cloth washers. Blackwater doesn’t have a single definition that is accepted nationwide. It is basically toilet and urinal water, as well as kitchen sinks in most areas.
50% Reduction
Intention:
- Limit or eliminate potable water (drinking water) use for landscape irrigation.
- Limit or eliminate use of natural surfaces for landscape irrigation.
Implementation:
- Use species factor
- consider size, growth rate, adaptability, texture, color, diversification of plant life on site
- Use high efficiency micro-irrigation system
- drip, micro misters, subsurface irrigation
- Instead of using potable water use:
- captured rainwater
- recycled wastewater
- treated water
- Use treated water conveyed by public agency as specifically for non-potable uses
Codes/Standards Applied:
- none
Extra Credit:
- none
Submittal Phase:
- design
Links from Reference Guide:
- Graywater Systems, Compost Toilets, & Rain Collection
- The Irrigation Association
- Texas Evapotranspiration Association
- Texas Water Development Board Web Site
- Water Wiser: The Water Efficiency Clearinghouse
Other Water Efficiency Credits
- WE 1.1 – Water Efficient Landscaping – Reduce by 50%
- WE 1.2 – Water Efficient Landscaping – No Potable Use or No Irrigation
- WE 2 – Innovative Wastewater Technologies
- WE 3.1 – Water Use Reduction – 20% Reduction
- WE 3.2 – Water Use Reduction – 30% Reduction
20 Comments On This Post
what is the difference between recycled wastewater and recycled graywater? the requirements state both.
Wastewater contains both Grey Water and Black Water.
Grey water is wastewater that comes from domestic usage like washing machines, showers, bathroom sinks.
Black water is wastewater that comes from urinals, dishwashers, kitchen sinks and contains food particles, feces and other hazardous/toxic materials.
Both grey and blackwater can be recycled for irrigation purposes, but recycling black water is a much more elaborate filtration process and much more expensive.
hi pat! do i have to memorize the calculations of all credits? im about to take the exam (24 nov) but im a little concerned about having to memorize every equation.
What is alternative mowing? It is one of the strategies mentioned to reduce potable water use for irrigation.
I’m confused about shading. In one area it says to plant shade trees to reduce green island effect (OK, lower evapotranspiration less irrigation). But later it says (under density factor), shading increases evapotranspiration. Can someone clarify this? Is shading a good strategy for this credit or not?
Jay, a little late and not from an expert, by far, but here goes. I think you may be confusing density and microclimate factors. Density discusses the amount of leaves which increases evaporation. Microclimate discusses the shading, or lack there of, which helps to reduce evaporation. It may appear counter intuitive because more leaves would mean more shade, right? Think of grass, tons of individual leaves, but all those leaves do nothing to shade the soil. Lastly, I think you are getting bogged down in the minutia of the details. This test isn’t about knowing how to actually do it, just to pretend you can.
A practice exam states:
Which 3 might contribute to WEc1:Water Efficient Landscaping?
A. planting of hardwood trees to provide shade
B. use of native or adapted species
C. substitution of turf grass for other types of vegetation
D. reduction of total landscaped area
E. a combination of vegetated swales and rain capture
Correct Answers: A, B, E
Is C not a correct answer b/c it says “other types” and would only be correct if replaced w/ native/adapted species?
And for answer E, I understand the rain capture, but how does vegetated swales contribute. I don’t find anywhere in the manual where it talks about them under WEc1.
good question. sounds correct cassi. if you replaced the grass with say ferns in the desert, you wouldn’t be saving a whole lot of water if any.
Vegetated swales by their nature capture rain water to slowly discharge (but also waters the plants in it over a drawn out time) as well as being densely populated with shrubbery (shade).
Cassi>
The way Im reading it, C is suggesting designers to substitute turf grass in place of other vegetation. This of course is incorrect, as you want to minimize turf grass.
@Parker,
This kind of wording seems to be an issue with LEED. The language should be written more clearly.
Pre test exam question
To calculate the baseline water use for WE Credit 1, a project team needs to use which factors?
A
Average Gallons of Irrigation Water used
B
Density Factor
C
July Median Temperature
D
Irrigation Efficiency
E
Species Factor
Answer b,d,e
I get B and e, but I thought the Irrigation efficiency was only calculated for design calculations, not baseline. As far as I can tell, the use of highly efficient irrigation systems can only be quantified by keeping them out of the baseline and adding the savings to a design calc. Hope that makes sense. The variable for irrigation efficiency is CE .. check out the calculations section. I am pretty sure this question is wrong.
Any ideas? Am i crazy?
@parker, The variable for irrigation efficiency is IE, which is a part of baseline calcs, CE is for controller’s efficiency, which is only included in design case. So D is correct answer for your ques.
Hope this makes it clear.
no you are not crazy..its just the exam fever;)
Is water from well or from nearby sanitary pipe applicable in WEc1 ?
This is in regards to Parker’s exam question:
The reference manual states that all calculations are based on irrigation during the month of July, I guess I’m not sure why C isn’t an answer. Could someone please explain this to me?
Has anyone tried to follow the example on page 122 of the reference guide (V2.2; Sept.’06)? They are calculating Total Potable Water Applied and should be calculating Total Water Applied. Their answer for TPWA is arrived at by using the formula TWA=Area x (ETL/IE). However their published formula for TWA is TWA=Area x (ETL/IE)x CE x .6233. In the narrative of the example, no mention is made of the controller efficiency (CE), so I presume that this is deleted from the equation in the sample. TPWA should only be calculated for the total landscape area and not each individual area since TPWA=TWA – Reused water. Am I missing something??
LEED FOR SCHOOS? Does anyone have a good website to answer questions.
Thanks
I’m confused, is there a minimum area required for landscaping? lets say I”m in an urban site and have two trees in the front of the building- if I only water them for one year does this qualify for 1.1 and 1.2?
I came to the same confusing conclusion regarding the example on page 122 – it has to be an error. They actually calculated the TWA for each landscape type not the TPWA. Furthermore the equation they have for TWA is not consistent with the calculations in Table 3 so I’m not sure which is correct – the Table 3 or Equation 3?
RE: What is alternative mowing? It is one of the strategies mentioned to reduce potable water use for irrigation.
By Dee on Nov 26, 2008
Still confused on that one myself. Not alot of info on this one but from what I can tell it means leaving the grass clippings on the lawn reducing fertilizer needs but as far as water reduction is concerned, my only geuss is that it works in the same way mulching does in preventing evaporation. anyone w/ any real knowledge on the subject could put my mind ocd mind at ease.
Thanks to In the Leed. I passed yesterday!
Thanks,
Dennis