Key Baseline Changes in 2009 Edition of WEc3, Water Use Reduction

I recieved a call from a project architect this morning who had designed a large LEED Core and Shell v2.0 project who in turn had received a call from another architect who is working on a LEED Commercial Interiors v3.0 (2009 edition) upfit of the same building. While we were able to earn 2 points for reducing expected water use by 30.1% in the LEED-CS submittal, when the upfit architects were looking at the water use reductions based on the LEED-CI requirements they determined that the anticipated reduction was only 10.8%. This level of reduction doesn't even meet the new 20% reduction requirement found in the WEp1, Water Use Reduction prerequisite!* What happened? Did we miscalculate the original submittal?

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We (or rather our consultant engineer) didn't miscalculate anything! After taking a closer look at comparing the calculations for both the v3 and v2 editions, we discovered that LEED has adjusted the baseline rate for public faucets from 2.2 gpm down to 0.5 gpm, meaning that while we had substantial flow rate reductions in the LEED-CS v2.0 submittal, none could be claimed for the LEED-CI v3.0 calculation even though the fixture specs were the same. The updated baseline standard applies to v3 editions of LEED-NC, LEED-CS, LEED-Schools, and LEED-CI systems. The change stems from the inclusing of the "maximum [flow rate] incorporated into the national Uniform Plumbing Code and the International Plumbing Code[s]" into the updated requirements. LEED-EB:OM v3.0 sets the anticipated baseline on these standards, but that was the case on the v2 edition as well so nothing has changed there from what I can see.

While the v2 baselines applied a 2.2 gpm baseline requirement for all bathroom lavatories, the v3 system distinguishes between 'public' and 'private' commercial restrooms and residential bathrooms. A private restroom is anything that would regularly be used by only one person at a time: hotel/motel guest bathrooms, hospital patient room bathrooms, and arguably bathrooms serving single offices (e.g. bathroom in the CEO's office used only by that person). All residential bathrooms and these private bathrooms are still held to the same 2.2 gpm baseline as before. Everything else (hotel lobby, shared office, school, and retail and restaurant bathrooms, etc.) are now held to the .5 gpm baseline.

I should point out that I think this is a good change... it's ridiculous to put anything other than a .5 gpm in sinks that will likely never be used for anything other than handwashing or perhaps brushing your teeth, especially when you consider a .5 gpm replacement aerator costs about $2. It also makes sense to keep private bathrooms to a higher standard, since people may be filling coffee pots or other containers that could be annoying if you were limited to such a low flow rate. I've installed a variable flow rate faucet in my kitchen that works great since I leave it on the low setting until I need to fill something up, but my bathroom sink uses a .5 gpm aerator. I should point out that people using on-demand water heaters may have problems in that the flow rate is so low that it may not trigger the water heater to turn on!

Bottom line... I think this is another instance of LEED moving in the right direction by tightening the requirements a bit, but people used to the v2 systems such as myself should definitely make a point to realize that a 20% reduction in v2 is not necessarily 20% in v3. Disagree with me? Please let me know by leaving a comment!

*I should note here that as the bathrooms in question are part of the shared core space of the facility, they should presumably not impact the LEED-CI calculations at all since they are outside of the scope of the upfit**, but any project that upgraded or is considering upgrading from a v2 system to it's v3 equivalent should take note of this change and evaluate the impact on their scores and ability to meet the WEp1 prerequisite.

**NOTE - 02.17.10 - Nathan has questioned the accuracy of the assumption that the existing fixtures would be outside of the scope of the prerequisite in the comments, and I don't have an 2009 IDC reference guide on-hand to refer to so I can provide a definitive answer. I've always been a little hazy on how the scope of a LEED-CI project is set, and since I don't have direct experience in LEED-CI I could very possibly be wrong!


Andrew said...

We're still working on trying to find a water-saving faucet for v3. If you don't have showers in your project, getting to 30% is near impossible even with the use of HET, waterless urinals, and low-flow pantry faucets.

Nathan said...

Regarding Andrew's comment above, my company's general feeling is that it takes the whole bag of low-flow fixtures to earn 1-2 pts (pint urinals, 0.5 GPM lavs, dual flush toilets, 1.5 GPM shower heads). To get the upper point thresholds, you have to move beyond just fixtures, probably using rainwater or greywater. I think this is a good thing.

Joel, I think you are wrong about the bathrooms being outside the scope. Under CI-2009 you need to account for whatever water fixtures the tenants will be using. If this is a TI space and they will use old CS bathrooms, then unfortunately you have to account for the old fixtures. If the tenants were providing their own new restroom facilities, then presumably the CS would not affect the calcs.

joelmckellar said...


I wouldn't be surprised to find you're correct... I made a note in the blog post saying as much... If you could provide definitive language on the subject from a reference guide or CIR I would be much obliged!

dave said...

We are finding we can still achieve significant water savings in projects (in terms of the LEED calcs, anyway) by using the metered faucet baseline (gallons per cycle) instead of the flow rate (gallons per minute). You just have to specify to set the faucet meters to the minimum period (usually 5-8 seconds) that the manufacturer permits.

Michael Kawecki said...

No offense, but you guys have missed a decimal point or something in your calculations. Between v2 and 2009 calculations, the lavs will only change the percentage 1-2%. I've had the exact same scenario with a CSv2 project with a CIv2009 moving in, and the only thing I had to change was to screw on a .5gpm aerator on the kitchen faucet in the break room.

It's still pretty easy to get close to a 30% reduction using nothing more than dual flush valves on the water closets, .5gpm on the urinals, and .5gpm aerators on the lavs. Start looking at HE fixtures, like pint urinals, and you easily pass 30%.

I developed a GBCI CE course specifically on this topic and had to look at multiple scenarios. I include the actual calculations for both v2 and v2009, 3 different scenarios - one of which is this same scenario. It's available via webinar if anyone is interested -

joelmckellar said...


I think the issue here is the scope of what's included in the water use calculations. If you have everything (shower, lavatory faucets, urinals, toilets, commercial prerinse spray valves) the ability to find reductions is different than if you only have a few of those components in the building. If you leave out a shower, it becomes more difficult to earn savings than if those are included in the scope. If somehow you only had public lavatory faucets and nothing else (retail?), it would be impossible to earn the credits (at least I'm not aware of anything lower than .5 gpm aerators).

Derek said...

Our company has asked USGBC twice now on clarifying whether to include water fixtures if they're not within the project scope. Both times they have indicated do NOT include them in the calculations even if tenants regularly use them. They say only add them into calculations if the project has directly installed or modified any water fixtures outside the project scope.

I also want to point out each of these reply emails have a little disclaimer at the bottom saying "The text above represents a staff opinion of a particular issue, and does NOT set any precedent to be upheld during a LEED Certification Review".

Nathan said...

That is really interesting to hear Derek. Here is the section of the LEED 2009 CI guide book that gives me pause (from the WEp1 description, Section 4- Implementation):

"The water use reduction credit is based on occupancy. When restrooms are not a part of the project scope, it is important to evaluate the plumbing in common areas of the building. If the base building does not have high-performance fixtures, the project team should consider requiring upgrades to existing fixtures as part of the lease negotiations."

"Should consider" is weak wording at best, but this seems to say you would need to upgrade core and shell restroom fixtures, or at least include them in the calculation.

John Koeller said...

What design professionals should realize is that the model codes (UPC, IPC, and NSPC) all reference the national standards when it comes to plumbing fixtures and fixture fittings and their maximum flow rate. The national ANSI standard for plumbing fixture fittings (faucets, showerheads, etc.) is ASME A112.18.1. For about 15 years, this standard has set the maximum flow rate for the faucets in question at 0.5 gpm, NOT the 2.2 gpm that appeared in prior versions of LEED. In truth, LEED screwed up (until 2009) by incorrectly setting a baseline flow rate that was non-compliant. LEED referenced EPAct 92 when, in fact, the model codes and national standard set the maximum well below the EPAct maximum. The failure of LEED to recognize this and allow for baselines that were not even close to code compliant is what has led in the past to many LEED credits being "earned" that really should not have been. Hence, when LEED corrected this problem in 2009, it looked like LEED was being overly aggressive in taking the threshold too low when really they were just establishing the baseline where it should have been all along.

Having been a part of the process on LEED's water Efficiency Technical Advisory Group for 6 years, I can tell you that it was exceedingly difficult to get USGBC to correct this significant error. Fortunately, it has finally been done and now projects are no longer living in the "water fantasy world" of undeserved credits.

John Koeller

Mr. Macko said...


I have read this issue extensively and will summarize my thoughts here. I also have posted something similar to this on other blogs but since this is a hot topic the facts need to be set straight.

First off I agree that the baseline should be .5 for everything where only minor hand washing after someone uses the facilities is expected. This is however not the legal and defined truth of the language.

I'll start by reiterating that LEED uses measurable standards as benchmarks. In this case we are talking about UPC and ASME setting the definition.

For this credit the devil is in the details... The definition of Private and Public is where your attention should be directed. It doesn't matter what LEED or the USGBC suggests as "types of private uses" - the fact is that they are saying be 20%(or 30, 40, etc) better than code.

So we dig into code...
The definition of public and private was set resulting from concerns about the classic "general public" using a lavatory faucet and burning themselves with hot water. They separated the two to protect the "general public" - the definition was set to guide the temperature at which hot water is allowed to be distributed to the faucet. It has nothing to do with usage, consumption or being eco.

So, knowing that information the facts guides the intent. The definition of "public" faucets are "lavatory faucets are those intended for the unrestricted use of more than one individual."

The 9th floor French Consulate bathroom in a building that has key-card access and a guard is not a facility intended for unrestricted use. Nor is an office space where the approximate water use based on FTE calcs is known on a daily basis. Furthermore, a school where students have to ask for a hall pass to go the bathroom is certainly not "unrestricted."

Again reiterating my piece that I agree with the intent of LEED, sadly the devil is in the details on this one.

Most recently it was for one of our projects - they were a defense contractor that mandated a passport and finger scanning for individuals entering the campus. I'll let you know what the LEED reviewer says...

I'd be interested to know from Joel Koeller if this was brought up at the TAG meetings. In my mind the USGBC has a loophole on this one... Won't be the first time of course!


ll said...

I work in the DC area, and have both toured the USGBC space, spoken with USGBC staff, and done several projects with the MEP firm that did the USGBC's latest office--GHT Ltd--who directly addressed the question of what fixtures are included in the water use calculations for LEED-CI spaces when doing the calculations for the USGBC tenant space.

According to these sources, under the prerequisite, only the fixtures within the tenant space and the tenant's scope of work are included in the WE reduction calculations.

However, when pursuing WE reduction CREDITS, all base building fixtures which the tenant may reasonably be considered to be likely to use--all core restrooms on the tenant floor or floors (even partial floors), penthouse amenities, fitness center amenities, etc., should also be included in the WE reduction calculations.

this and other items are addressed in the addenda to the reference guide, found here:

Anonymous said...

That seems extra confusing to have different calculations for WEp1 and WEc3.

Following this logic, if the tenant space has NO water fixtures then it cannot qualify for LEED. If no water is used in the tenant space then it's impossible to get a 20% improvement.

Anonymous said...

Following your link, for LEED-CI, both WEp1 and WEc1 were changed to tenant space instead of building. I still wonder if there are no water fixtures in the tenant space.

Page 108
13. Definitions WEp1 Water Use Reduction Insert the term “Tenant space” in alphabetical order with the accompanying text "Tenant space is the area within the LEED
project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space." 1/8/2010

Page 111*
Intent WEc1 Water Use Reduction In the first line of the paragraph, replace the word “buildings” with “tenant space” so the text becomes “…efficiency within tenant spaces to reduce…” 11/2/2009

Brandon Smith said...

I knew that I had run across something that had addressed the idea of "tenant space without water use fixtures". I had to do some searching through old CIRs but managed to find a ruling (under v2.0) that directly answered the question as to whether or not fixtures located outside of the project premises needed to be included under the 20% prerequisite.

According to the ruling the prerequisite/credit ".... requires that the design case achieve a 20% reduction in aggregate water use from the calculated baseline for the tenant space. The calculations of this credit need to include all fixtures necessary to meet the needs of the occupants...". It goes on to further say that the project team should "...first establish the water use baseline by including all fixtures to be used by tenants INCLUDING the central core restrooms....".

Although the USGBC makes mention that they've modified the CIR process for v3.0 and that v2.0 CIRs may have no standing within the updated system, I believe that the intent of the prerequisite has been made pretty clear through the aforementioned CIR.

I verified that this was correct with a group here in California that had also recently gone through the process with a tenant space that included no restrooms (we're currently pursuing LEED Silver on a data center with only common area restrooms ourselves). She confirmed that they were required to meet the 20% reduction by ensuring that high efficiency fixtures were incorporated into the buildings core restrooms.

Personally, although I'm sure we could ask dozens of persons who've gone through the process, I'd err on the side of credit intent and include all fixtures integral to the tenant space regardless of whether or not they fall within either the project scope or the LEED boundary.