Back to top
4

WATER

4:WATER

Water quality and conservation practices impact our health and well-being, property operating expenses, and a limited precious resource.

 

4.1

Mandatory

Water-Conserving Fixtures

RATIONALE

Water conservation translates into direct utility savings for residents and building owners and lowers infrastructure costs associated with stormwater management and water treatment facilities. Reduced water pressure saves water, conserves energy and helps ensure proper operation of fixtures and appliances.

REQUIREMENTS

Reduce total indoor water consumption by at least 20% compared to the baseline indoor water consumption chart below. Any new toilet, showerhead, and/or lav faucet that is installed in the project must be WaterSense® certified, in addition to the project’s total indoor water consumption meeting the minimum 20% improvement threshold.

The Enterprise Green Communities Water Calculator is available to calculate and compare your project per-person per-day indoor water consumption to the baseline water consumption chart below (adapted from: LEED v4.1 Water Use Reduction Calculator). When making your comparison, assume that the baseline project has the same type of fixtures as your project in question. For instance, if your project does not include dishwashers, do not include dishwasher water consumption in your baseline project calculation for comparison.

AND

For all single-family homes and all dwelling units in buildings three stories or fewer, supply pressure may not exceed 60 PSI and should be controlled by pressure regulator if necessary. Piping for fire sprinkler systems is excluded from this requirement and should comply with state and local codes and regulations as well as manufacturer specifications.

BASELINE INDOOR WATER CONSUMPTION (per person per day)

FIXTURE

BASELINE FLUSH OR FLOW RATE

ESTIMATED FIXTURE USAGE

ESTIMATED WATER USAGE

Shower (per compartment)

2.5 gpm

6.15 minutes

15.4 gallons

Lavatory, kitchen faucet

2.2 gpm

5.0 minutes

11 gallons

Toilet

1.6 gpf

5.05 flushes

8 gallons

Clothes washer

8.4 WF* top loading and

4.7 WF front loading

0.37 cycles @ 3.5 ft3

13.2 gallons top loading

7.4 gallons front loading

Dishwasher

5.0 gpc standard and

3.5 gpc small

0.1 cycles

0.5 gallons standard and

0.4 gallons small


*WF = Water Factor

 

RECOMMENDATIONS

  • Certain existing fixtures, such as bathroom faucets, can be retrofitted with aerators rather than be replaced to reduce water flow to the requisite level. Note that WaterSense labeled aerators are available and recommended.
  • Dual-flush toilets have an average flow rate calculated and provided by the manufacturer. However, if you are not able to locate this information on the packaging, use a 2:1 ratio for low-volume flush to high-volume flush to determine the average flow rate. For example, with a dual-flush toilet that has a 0.8 low-volume flush and a 1.6 high-volume flush, the calculation to determine the average would be: 

  • (0.8 gpf x 2) + (1.6 gpf x 1) / 

    3

    = 1.067 gpf

  • For senior projects, consider using single-flush toilets that meet the criterion flow rates rather than dual-flush toilets. Feedback from past Enterprise Green Communities projects suggests that senior populations may be unsure of the dual-flush technology, which may lead to difficulty in operating the toilets in an effective and appropriate way.

RESOURCES

  • Products and services that have earned the WaterSense label have been certified to be at least 20% more efficient than the baseline, without sacrificing performance. For instance, not all toilets—even high-efficiency toilets—operate equally well. Poor performance can lead to the need for multiple flushes, creating higher than anticipated water consumption. To correct for this, the EPA’s WaterSense program certifies toilets that achieve water efficiency and operational effectiveness. Information on WaterSense products and services is available at www.epa.gov/watersense

  • Maximum Performance (MaP™) Testing. The MaP testing project was initiated in 2003 to test toilet models’ performance. This testing protocol simulates real-world use to help consumers identify high-efficiency toilets that not only save water but also work well. The current MaP testing report provides performance information on 470 toilet models. This site provides access to the complete listings of the tested toilets. www.map-testing.com

  • U.S. Environmental Proctection Agency, WaterSense Resource Manual for Building WaterSense®. WaterSense Labeled Homes and the WaterSense Water Budget Tool, which may be used to predict project water consumption. www.epa.gov/watersense/homes

  • Two performance-based home modeling tools which result in a 0-100 score are: HERSh2o (www.resnet.us/) and Water Efficiency Rating Score (WERS) (www.wers.us/)

4.2

Optional | 6 points maximum

Advanced Water Conservation

RATIONALE

Water conservation translates into direct utility savings for residents and building owners and lowers infrastructure costs associated with stormwater management and water treatment facilities.

REQUIREMENTS

Reduce total indoor water consumption by at least 30% compared to the baseline indoor water consumption chart below. Any new toilet, showerhead, and/or lav faucet that is installed in the project must be WaterSense certified, in addition to the project’s total indoor water consumption meeting the minimum 30% improvement threshold.

The Enterprise Green Communities Water Calculator is available to calculate and compare your project per-person per-day indoor water consumption to the baseline water consumption chart below (adapted from: LEED v4.1 Water Use Reduction Calculator). When making your comparison, assume that the baseline project has the same type of fixtures as your project in question. For instance, if your project does not include dishwashers, do not include dishwasher water consumption in your baseline project calculation for comparison.

PERCENTAGE OF REDUCTION IN

TOTAL INDOOR WATER CONSUMPTION

NUMBER OF

OPTIONAL POINTS

30%

3 points

40%

4 points

50%

5 points

60%

6 points

BASELINE INDOOR WATER CONSUMPTION (per person per day)

FIXTURE

BASELINE FLUSH

OR FLOW RATE

ESTIMATED

FIXTURE USAGE

ESTIMATED

WATER USAGE

Shower (per compartment)

2.5 gpm

6.15 minutes

15.4 gallons

Lavatory, kitchen faucet

2.2 gpm

5.0 minutes

11 gallons

Toilet

1.6 gpf

5.05 flushes

8 gallons

Clothes washer

8.4 WF* top loading and

4.7 WF front loading

0.37 cycles @ 3.5 ft3

13.2 gallons top loading

7.4 gallons front loading

Dishwasher

5.0 gpc standard and

3.5 gpc small

0.1 cycles

0.5 gallons standard and

0.4 gallons small

*WF = Water Factor

RECOMMENDATIONS

See Recommendations for Criterion 4.1.

RESOURCES

See Resources for Criterion 4.1.

4.3

Mandatory and Optional | 11 points maximum

Water Quality

RATIONALE

The quality of drinking water in the U.S. is regulated tightly and, according to the American Association for the Advancement of Science, remarkably safe. However, there are homes with people at high risk, vulnerable populations with frequent exposure to sources of lead. For instance, “lead-free” plumbing fixtures were permitted to contain up to 8% lead by weight until 2014. Today the allowable threshold for that label (which all new plumbing fixtures are required to achieve) is 0.25%. Lead pipes were banned in new systems in 1986, and yet, according to a study by the American Water Works Association, nearly a third of U.S. water systems still contained lead service lines in 2016. Properties that are served by private wells are particularly likely to have lead in drinking water. No level of lead exposure is safe, and exposure can lead to long-term learning and behavioral problems.

Legionnaires’ disease is less common, and most healthy people who are exposed to Legionella do not get sick. However, adults 50 years or older, current or former smokers, and people with a weakened immune system or chronic disease are at increased risk, if exposed.

Also consider the interplay between water conservation and quality—low flow fixtures may inadvertently exacerbate water quality degradation, if water is allowed to age in a system and pipes are not “right-sized” to prevent excessive stagnation.

REQUIREMENTS

Mandatory for Substantial Rehabs of buildings built before 1986. Optional for all other building types. [3 points]

Replace lead service lines. Determine whether a lead service line (LSL) connects the drinking water main under the street with the building. To determine if the service line is lead, contact the utility company for guidance and inspect the line where it enters the property. See www.lslr-collaborative.org/intro-to-lsl-replacement.html for additional guidance. If an LSL is present, replace it before or while replacing the water heater. Follow American National Standards Institute (ANSI) /American Water Works Association (AWWA) C810-17 Standard when replacing the LSL. Full LSL replacement evolves elimination of lead pipe from a water main up to the interior plumbing of the building.

Mandatory for multifamily buildings with either a cooling tower, a centralized hot water system, or more than 10 stories in height.

Develop a Legionella water management program within Criterion 8.1. Include keeping hot water above 140°F until the point of use and strategies to ensure that water does not stagnate in unused pipe sections or vacation locations.

Optional, all project types. [8 points]

Test water from dwelling unit faucets for water quality and remediate as indicated below. For testing bottles and instructions, contact an EPA approved lab. Find labs near you via this site, www.epa.gov/dwlabcert/contact-information-certification-programs-and-cer..., or by calling the Safe Drinking Water Hotline at 1-800-426-4791 for the address and phone number of your state laboratory certification officer to find certified labs near you.

  • Test water from dwelling unit faucets for the presence of lead. If results are above 0, install NSF/ANSI 58 or NSF/ANSI 53 filters in all units and replace these over time per manufacturer’s instructions. If lead results are above 10 ppb, replace all fixtures with NSF 61 certified fixtures. Particularly recommended for rehabs of buildings built before 2014 and in all buildings served by private wells.
  • In all buildings served by private wells, also test water from dwelling unit faucets for the following and remediate as indicated:

    • Nitrates. If results are above 50 mg/L (or above 11 mg/L for nitrogen), install an ion exchange or reverse osmosis water treatment system and test annually to make sure the problem is controlled.

    • Arsenic. If results are above 0.01 mg/L, follow remediation guidance from your local health department.

    • Coliform bacteria, to indicate whether or not E. coli is present. If coliform bacteria is above

      0 CFU/100 mL total coliforms (including E. coli), notify all residents not to drink water unless it is boiled it for at least one minute at a rolling boil, longer if at high altitudes. Disinfect the well according to procedures recommended by your local health department. Monitor your water periodically after disinfection to make certain that the problem does not recur. If the contamination is a recurring problem, investigate the feasibility of drilling a new well or install a point-of-entry disinfection unit, which can use chlorine, ultraviolet light. or ozone.

RECOMMENDATIONS

  • Some water utilities and municipalities offer financial incentives for replacing lead service lines; check with your local agencies.

  • For all properties—new construction as well as rehab—ensure that water is flushed regularly, rather than risking long periods of time between when water enters the system and when it is used. When water stagnates, quality may degrade considerably. As water ages in a system, disinfectant residual will decay, reducing chlorine residuals. This may lead to increased corrosion in copper and lead pipes and increased microbial regrowth, including Legionella. The less that water is allowed to age in a system, whether through thoughtful plumbing system design and/or flushes with municipal water, the less likely these issues are to occur. Note that each tap in the property will have a different stagnation rate, depending on use, and a different risk profile, depending on pipe and fixture materials. Consider design and testing carefully for each use of water in the property.

  • All community water systems prepare a Consumer Confidence Report for their customers by July 1 of each year. Contact your water utility to receive a copy of their latest report.  www.epa.gov/ccr

  • Install and regularly replace individual filtration systems.

  • 13% of the U.S. population receives drinking water from private wells and are not required by federal or state government to remediate quality issues if found, if those wells serve fewer than 100 people. See the National Center for Water Quality Research for guidelines. https://ncwqr.org/water-testing/well-water-testing/

RESOURCES

  • RCAC. Supports rural communities through financing, trainings and TA on water infrastructure issues, including compliance with the Safe Drinking Water Act and Clean Water Act. www.rcac.org

4.4

Optional | 4 points

Monitoring Water Consumption and Leaks

RATIONALE

In some cases, leaks may be the largest driver of project water consumption. Properly installed water- using fixtures, equipment, and appliances should not leak. However, over time, leaks may occur and should be resolved.

Monitoring water consumption by fixture, dwelling unit, or riser allows more nuanced understanding and management of water consumption than the typical whole-building meter.

REQUIREMENTS

Conduct pressure-loss tests and visual inspections to determine if there are any leaks; fix any leaks found. Visual inspections shall include checking for leaks at all accessible, visible water supply connections, and valves for water-using fixtures, appliances, and equipment.

Install an advanced water monitoring and leak detection system capable of identifying and shutting water off during anomalous water use events, or install a device to separately monitor water consumption in each of the following areas of the project:

  • Choose one from these three options:

    • Each cold branch off the apartment line riser for each dwelling unit
    • Each cold water riser and domestic hot water/cold water feed for each building

    • Every toilet in the project has technology that allows remote monitor readings

  • Common project laundry facilities, if such facilities exist

  • Boiler makeup water, if such boiler exists

  • Outdoor water consumption

  • Water consumption in any non-residential spaces of the project, where the property owner is responsible for water utilities

RECOMMENDATIONS

  • Note that for single-family homes with only one water supply to the home, the inspector will attach a pressure gauge to an outside faucet, take a reading and then shut off the municipal water supply to the house. After several minutes, the inspector will determine if the pressure has dropped. A loss of pressure indicates an unseen leak. For homes with more than one water supply or without an outdoor faucet, inspectors will attach a pressure gauge to the cold water faucet for the washing machine hookup or other cold water faucet and take the pressure reading. Conducting a pressure- loss test on dwelling units in multifamily buildings will vary based on the plumbing system design. Dwelling units that are supplied through a single line with a shut-off can be tested at any point of use. The pressure loss test can most easily be done here at a washer hookup or at any fixture using an adapter. For buildings that use riser pipe layouts, the test is simplest at the whole building level.
  • As a first step, when designing the plumbing system for a multifamily building, consider supplying each unit with a single pipe source and stubbing out for a meter to facilitate individual unit submetering. This will reduce costs associated with having to install multiple meters/monitors for several points of use attached to a single riser pipe.

  • When selecting equipment that is best suited for accurately measuring water use in each unit, note that water use within individual units will fluctuate between low and peak flows depending on the unit’s occupancy and the time of day. We recommend positive displacement meters, but consult with the meter or monitor manufacturer to select an appropriately sized device for the application. The building’s and the individual units’ size, function, fixture types, usage, occupancy, and peak population will influence minimum and maximum flow rates and proper sizing.

  • Note that improper installation can lead to metering/monitoring inaccuracies. In general, we recommend installing meters and/or monitors in an accessible location to allow for reading and repair and in a location protected from potential damage. And, to ensure uniform flow entering and exiting the meter or monitor, we recommend locating the monitoring device where there is sufficient length of straight pipe before and after the device. Consider installing a strainer to prevent debris and sediment from entering the meter/monitor and causing reading inaccuracies.

  • We recommend that in‐line meters or monitors meet AWWA standards and include a pulse output (1 pulse per gallon is desirable). Note that some vendors package water monitors with a remote data monitoring system. Other vendors offer only monitors or only remote data monitoring systems; these may be paired. And note that remote data monitoring systems come in a variety of forms: some are wireless and others require that they be hard‐wired. With either type, typically the water consumption data is sent from each meter/monitor to a datalogger inside the building, which passes it on to a website where it can be reviewed and downloaded. In cases where staff do not have time to review data for dozens of submeters/monitors, the website can be text or email alarm when a leak is suspected. Because it is easy to set up alarms, it is not necessary to dedicate an employee or outside firm to monitor the water data, but it is desirable and should be considered. We recommend consulting with the property owner and operations staff to determine whether a remote monitoring system is appropriate for the property.

  • Note that in‐line meters/monitors should be installed by a licensed plumber. We recommend a press‐fit pipe joining system instead of sweated joints for these installations, if also allowed by the manufacturer. Such a system saves labor costs and permits otherwise impossible installations. Remote data‐gathering systems are often installed by a controls or telecom contractor or, more expensively, by a licensed electrician. We recommend care in ensuring that every meter/monitor is installed so that it may be easily accessed for repairs or for manual reading (should that become necessary)—meters/monitors in cramped or inaccessible locations frequently are ignored or forgotten. Experience shows that domestic water systems frequently include long pipe runs without any shut-off capability, which make future repairs more difficult and/or disruptive. We recommend installing a few extra well‐placed isolation valves. Similarly, in new construction in particular, we recommend designers prioritize placing pipes in accessible locations when possible, either by exposing them or placing them behind an easily‐removable access door or chase. Pipes in an easily‐ removable chase are generally easier to repair and inspect and may be isolatable enough to eliminate water damage from a pipe burst or joint leak. We also recommend considering additional electrical outlets in basements to allow for the installation of the data gathering system described here.

RESOURCES

4.5

Optional | 4 points

Efficient Plumbing Layout and Design

RATIONALE

Efficiently designed hot water delivery systems reduce the amount of time it takes hot water to reach a fixture, saving both water and energy. Approximately 10%–15% of the energy use associated with the hot water delivery system is wasted in distribution losses, waiting for hot water to arrive at the point of use.

REQUIREMENTS

To minimize water loss from delivering hot water, the hot water delivery system shall store no more than 0.5 gallons of water in any piping/manifold between the fixture and the water heating source or recirculation line.

To account for the additional water that must be removed from the system before hot water can be delivered, no more than 0.6 gallons of water shall be collected from the fixture before a 10°F rise in temperature is observed.

Recirculation systems must be demand-initiated. Systems that are activated based solely on a time and/ or temperature sensor do not meet this requirement.

Ensure that your project is still meeting all relative local codes and requirements. Codes such as the 2018 Universal Plumbing Code and 2017 WE-Stand employ “right-sized” plumbing techniques that supersede and automatically comply with this requirement.

RECOMMENDATIONS

  • Effective and efficient distribution of hot water requires a whole-system approach and can be challenging to many builders. Considering the hot water delivery system early in the design phase and carefully following a plumbing design can deliver superior homes and reduced installation costs.
  • A hot water distribution system with less stored water in its piping will waste less water and energy. The length of piping between the water heater and each fixture, the pipe diameter, and piping material can all have a great cumulative impact on the efficiency of hot water delivery.

  • Insulation of hot water pipes can improve the efficiency of a hot water distribution system. Insulation of hot water pipes reduces the rate of heat loss and can deliver water that is 2°F to 4°F hotter than uninsulated pipes can. Pipe sleeves made with polyethylene or neoprene foam with thicknesses of either ½ or ¾ inch are the most commonly used insulation. The pipe sleeve inside diameter should match the diameter of the pipe for a close fit. Securing insulation every one or two feet using tape, wire, or cable tie will also help to fit insulation close to the pipe. Insulation should be used along the entire length of hot water pipes, including elbows and joints, but should be kept 6 inches away from the flue of gas water heaters. Insulation performs better with an R-value of R-3.0 or greater.

  • Consider central core plumbing, and/or multiple stacked central core plumbing layout, locating the water heater very close to hot water fixtures. Avoid dead legs at all costs.

RESOURCES

4.6

Optional | 6 points maximum

Non-Potable Water Reuse

RATIONALE

Rainwater and greywater reuse strategies reduce the need for municipal water supplies and sewage treatment. This is also an important resilience strategy, as it offers some level of protection and stability against drought or interruptions in water supply.

REQUIREMENTS

Harvest, treat and reuse rainwater and/or greywater to meet a portion of the project’s non-potable water needs. Install backflow preventers or other methods of cross-connection protection at any junctions with the greywater systems.

To achieve optional points, provide the defined percentage of the project’s non-potable water needs which will not be met with a potable water source—instead, through rainwater and /or greywater.

TOTAL NON-POTABLE WATER NEEDS

SUPPLIED BY NONPOTABLE SOURCES
(RAINWATER AND/OR GREYWATER)

NUMBER OF

OPTIONAL POINTS

10%

3 points

20%

4 points

30%

5 points

40%

6 points

RECOMMENDATIONS

  • In some cases, employing rainwater and greywater harvesting, treatment and reuse can provide for all of a project’s water needs. However, use is subject to state and local regulations and special requirements, and in some jurisdictions these systems may not be allowed. Check with your local building code officials for requirements.

  • Non-potable water recommended for residential application can be provided by harvested rainwater using rain barrels or cisterns or by obtaining reclaimed water from the municipality. Rainwater and reclaimed water do not meet potable water standards and therefore have limited use applications. These water sources can supply water for non-spray irrigation and other outdoor water needs during periods of drought but are never suitable for human consumption. Proper signage should be displayed on the structure to caution users that the water source is non-potable.

  • Rainwater can be harvested from impervious surfaces such as roofs and carried via gutters and downspouts to a storage tank or cistern where it can be treated or filtered for potable uses. Untreated rainwater may be used for non-potable uses.

  • Greywater may be stored and treated for non-potable uses such as toilet flushing and irrigation.

RESOURCES

4.7

Optional | 8 points

Access to Potable Water During Emergencies

RATIONALE

During power outages, access to water for drinking and sanitation needs is often one of the greatest challenges. During a power failure, residential buildings using electric pumps lose their supply of potable water.

REQUIREMENTS

Provide residents with ready access to potable water in the event of an emergency that disrupts normal access to potable water. Choose one of the following options:

Option 1

In buildings where on-site electrical pumps are used to transport water to upper floors, provide residents with access to potable water at a location where containers can be filled and brought to apartments. Ensure that this access point is located above flood level and that it may be accessed safely and relatively easily in times of power loss (e.g., a public restroom on a lower floor).

OR

Option 2

Provide stored potable water that can be used during times of emergency totaling 10 gallons per resident per day for a minimum of four days. Note potability as well as storage size and weight considerations.

OR

Option 3

Provide a drilled well with a means for pumping water when the electric grid is down (e.g., hand pump, portable generator serving pump, gravity-flow spring).

RECOMMENDATIONS

  • In many cities, pressure typically brings water up to the fifth or sixth floor of taller buildings, with pumps used to deliver water to higher floors. If the power grid fails and backup generators are not connected to water pumps or if they fail, residents should have access to a place in a common room to fill containers with potable water. This could be a centrally accessible corridor or utility closet. Specifics will vary by project.

  • In more rural areas that rely on on-site water rather than municipal water, advanced, modern hand pumps can provide a resilient water supply.

  • Harvested rainwater or pumped water can be stored on top of buildings, in utility space in buildings, or in separate water tanks.

  • For properties that use roof-top tanks to maintain pressure, it may be possible to utilize these tanks as a source during emergencies with proper controls and access.

RESOURCES

  • Enterprise Green Communities, Ready to Respond Toolkit. Includes more than a dozen strategies and specific guidance for building property resilience in the event of an emergency, including access to potable water. www.enterprisecommunity.org/resources

 

“Being able to afford your bills … as you grow older, this becomes more and more important.”
Resident of Enterprise Green Communities property

INTRODUCTION

CRITERIA CHECKLIST

      • INTEGRATIVE DESIGN

      • LOCATION +

        NEIGHBORHOOD FABRIC

      • SITE IMPROVEMENT

      • WATER

      • OPERATING ENERGY

      • MATERIALS

      • HEALTHY LIVING ENVIRONMENT

      • OPERATIONS,

        MAINTENANCE +

        RESIDENT ENGAGEMENT APPENDICES

        GLOSSARY