Among the more prominent issues facing us today is water conservation and using water more efficiently. In this respect, the LEED Water Efficiency (WE) section now addresses water holistically, looking at indoor use, outdoor use, specialized uses, and metering. Likewise, LEED has raised the bar for water conservation and now requires all projects to reduce water use by at least 20% as a prerequisite to LEED certification, whereas earlier versions of LEED awarded a point for a 20% reduction. This prerequisite was first introduced in LEED 2009 and is significantly more demanding plus it does not apply to earlier versions of LEED. The baseline is determined by assuming that all fixtures meet national codes, as laid out on a fixture-by-fixture basis in the credit requirements. As for LEED for Existing Building, the Operations & Maintenance threshold depends on when the facility was originally constructed or last renovated. Of note, those following the same WE requirements as LEED for New Construction include: LEED for Commercial Interiors, LEED for Core and Shell, LEED for Schools, LEED for Retail, and LEED for Healthcare.

Recent Environmental Protection Agency (EPA) estimates place the amount of freshwater, i.e., water needed for drinking, industry, and sanitation at about 2.5% of the world’s total. Roughly, one-third of this is readily accessible to humans via lakes, streams, and rivers. Demand for freshwater continues to rise, and if current trends continue, experts project that demand for freshwater will double within the next three decades. Since 1950, the United States population has increased by almost 90%. In that same time span, public demand for water increased by 209%. Americans now use an average of 100 gallons of water per person each day. This increased demand has put tremendous stress on water supplies and distribution systems, threatening both human health and environment. Reacting to this potential crisis, the South Nevada Water Authority has put into place a Water Efficient Technologies program that offers financial incentives for capital expenditures when businesses retrofit existing equipment with more water-efficient technologies. Likewise, the EPA has launched WaterSense, a water-oriented counterpart to the ENERGY STAR program that promotes water efficiency and aims to boost the market for water-efficient products, programs, and practices.

In addition, local codes are not always keeping pace with some of the new green codes (e.g., the IgCC) and emerging technologies which are not code compliant but are nevertheless available in the marketplace. These include, gray water systems, rainwater collection systems, high-efficiency irrigation systems, recirculating shower systems, regulations controlling hot water delivery, recirculation of hot water, insulation of hot water piping, demand-type tank-less water heaters, water softeners, and drinking water treatment systems, all of which are being implemented through EPA WaterSense. The EPA estimates that toilets account for roughly 30% of the water used in residences, and Americans annually waste 900 billion gallons by the use of old, inefficient toilets. By replacing an older toilet with a WaterSense labeled model, a family of four could reduce total indoor water use by about 16% and, depending on local water and sewer costs, save more than $90 annually.

Moreover, water conservation translates into energy conservation and savings. By just 1 in every 10 homes in the United States installing WaterSense-labeled faucets or aerators in their bathrooms, in aggregate, this could result in a saving of about 6 billion gallons of water, and more than $50 million in the energy costs to supply, heat, and treat that water. The EPA also estimates that if the average home was retrofitted with water-efficient fixtures, there would be a savings of 30,000 gallons of water per year. If only 1 out of every 10 homes in the United States upgraded to water-efficient fixtures (including ENERGY STAR–labeled clothes washers), the resultant savings could reach more than 300 billion gallons and nearly $2 billion annually. This could have a significant positive economic impact on small plumbing contractors and small businesses throughout the various sectors. In fact, the recent increased demand and focus on water efficiency can provide a powerful catalyst to helping the emerging water and energy conservation market to revitalize these industries across the country at a time when most small business owners are suffering because of tough economic times.

According to Alliance for Water Efficiency, NFP, “Typical water use efficiency categories within many of the national green building programs (guidelines and standards) include:

The US EPA estimates that an American family of four uses about 400 gallons of water per day. About 30% of this is used outdoors for various purposes including landscaping, cleaning sidewalks and driveways, washing cars, and maintaining swimming pools. Nationally, landscape irrigation counts for almost one-third of all residential water use. This amounts to more than 7 billion gallons per day. Water Efficiency is one of the principal categories of the LEED Rating System and the number of WE credits available depend on the type of certification sought, e.g., New Construction, Commercial Interiors, Schools, etc. However, meeting LEED’s Water Efficiency Credit 3-Water Use Reduction is no longer a sure thing, even for commercial office buildings. Moreover, recent feedback from GBCI states that municipally treated process water is no longer acceptable for alternative compliance paths for WEp1 and WEc3 (LEED V3), and municipally supplied gray water may not be used to gain water savings in this prerequisite.

For New Construction, a total of 10 possible points (5 points were allotted to previous versions) can be achieved for Water Efficiency (WE) LEED V3 certification (WE Credits for LEED-Homes: Maximum 15 points possible). The main WE categories and topics to know for LEED N/C include the following:

Landscaping irrigation is the main source of outdoor water consumption, accounting for about 30% of the 26 billion gallons of daily water consumption. The intent of water-efficient landscaping in the LEED rating system is to reduce (by at least 50%) or eliminate the amount of potable water consumption and natural surfaces or subsurface water resources available on or near the project site and used for landscape irrigation.

Best practice strategies:

On occasion, landscape design strategies alone are unable to achieve a project’s irrigation efficiency goals, in which case attempts should be made to meeting efficiency demands through optimization of the irrigation system design. For example, use of high-efficiency drip, micro and subsurface systems can reduce the amount of water required to irrigate a given landscape. The USGBC reports that drip systems alone can reduce water use by 30–50%. Climate-based controls, such as moisture sensors with rain shutoffs and weather-based evapotranspiration controllers, can further reduce demands by allowing naturally occurring rainfall to meet a portion of irrigation needs. To earn a LEED WEc3 credit, a reduction is needed in the use of potable water for irrigation by 50–100% compared with a baseline irrigation system typical for the region. Because landscape irrigation can account for nearly 40% of the average office building’s potable water consumption, reducing or eliminating potable water use for landscaping can save both water and money. For LEED certification, one point is awarded for a 50% reduction in water consumption for irrigation from a calculated mid-summer baseline case, and a total of two points for a 100% water reduction. While LEED V3 has made it increasingly difficult to obtain WE points, it should have a positive impact on architects and plumbing engineers by continually challenging them to develop creative solutions that reduce building potable water consumption.

To facilitate in greening the supply, it is necessary to tap alternate water sources. LEED recognizes two alternate water sources: rainwater collection and wastewater recovery. Rainwater collection involves collecting and holding on-site rainfall in cisterns, underground tanks, or ponds during rainfall. This water can then be used during the dry periods by the irrigation system. Wastewater recovery can be achieved either on site or at the municipal scale. On-site systems capture gray water (which does not contain human or food processing waste) from the building and apply it to irrigation. Reductions shall be attributed to any combination of the following approaches, including:

Additionally, groundwater seepage that is collected and pumped away from the immediate vicinity of foundations and building slabs are eligible for being used for landscape irrigation to meet the intent of this credit. It must be demonstrated, however, that doing so does not impact the site stormwater management systems. When a landscaping design incorporates rainwater collection or wastewater recovery in particular, it is essential to assemble a team of experts and establish project roles at an early stage in the process. Rainwater collection and wastewater treatment systems stretch over multiple project disciplines, making it particularly important to clearly articulate responsibilities. Having an experienced landscape architect on board is pivotal for a water-efficient landscape and irrigation system design. It is highly recommended to plan early to take advantage of the available LEED points for water-efficient landscaping credits.

Several of the LEED credits deal with gray water and blackwater. Gray water has several definitions; it is typically considered to be untreated wastewater that has not come into contact with toilet waste, such as shower water, water from sinks (other than the kitchen), bathtubs, wash basins, and clothes washers. Gray water use generally includes indoor and outdoor reuse. When used outdoors, the gray water is usually filtered and then used for watering landscape. Indoor gray water use on the other hand, consists of recycled water and is used mainly for flushing toilets. Gray water has other applications including construction activities, concrete mixing, and cooling water for power plants. The Uniform Plumbing Code (UPC) defines gray water as untreated household wastewater that has not come in contact with toilet waste, whereas the International Plumbing Code (IPC) defines it as wastewater discharged from lavatories, bathtubs, showers, clothes washers, and laundry sinks; some jurisdictions allow the inclusion of kitchen sinks to be included with gray water. Blackwater lacks a specific definition that is accepted nationwide but is generally considered to constitute toilet, urinal, and kitchen sink water (in most jurisdictions). However, depending on the jurisdiction, implementing gray water systems that reuse wastewater from showers and sinks for purposes such as flushing of toilets or irrigation may encounter code compliance restrictions.

One of the best ways to increase water efficiency in buildings is through plumbing fixture replacement and implementation of new technologies, particularly since significant water efficiency improvements over conventional practice are now readily achievable. Replacing older, high-flow water closets and flush valves with models that meet current UPC and IPC requirements is important. While current codes require the lower flow rate for new fixtures, existing buildings often have older, high-flow flush valves. Despite the tremendous water savings available by updating the fixtures, facility managers often avoid the upgrade because of concerns about clogging. Solid waste removal must be 350 g or greater. Fixtures Pass or Fail based on whether the fixture can completely clear all test media in a single flush in at least four of five attempts. Toilets that pass qualify for the EPA WaterSense label. It should be noted that when the Energy Policy Act of 1992 was first enacted, many facility managers at the time experienced problems with the low-flow fixtures clogging due to fixture-design issues which have long since been addressed (Tables 8.1a and b).

The value of selecting water-efficient fixtures will not only reduce sewer and water bills, but efficient water use reduces the need for expensive water supply and wastewater treatment facilities and helps maintain healthy aquatic and riparian environments. Moreover, it reduces the energy needed to pump, treat, and heat water. Water is employed in a product’s manufacture, during a product’s use, and in cleaning, which means that water efficiency and pollution prevention can occur during several product life cycle stages. Mark Sanders, product manager for Sloan Valve Company’s AQUS Greywater System says, Gray water and reclaimed water strategies make good use of water resources, especially when implemented in conjunction with efficient plumbing systems.

The maximum volume of water discharged, using both original equipment tank trim and using after market closure seals, shall be tested according to the protocol detailed on the WaterSense website. There are two primary approaches to measuring Water volume: gallons per flush for toilets and urinals or gallons per minute for flow-type fixtures such as lavatories, sinks, and showers. Metered faucets with controlled flow rates for preset time periods are measured in gallons per cubic yard. The maximum volume of water that may be discharged by the toilet, when field adjustment of the tank trim is set at its maximum water use setting, shall not exceed 1.68 gpf for single flush fixtures and for dual flush fixtures should not exceed 1.40 gpf in reduced flush mode and 2.00 gpf in full flush mode.

For LEED purposes, baseline calculations should be computed by determining the number and gender of the users. As a default, LEED lets you assume that females use toilets three times per day males once per day in addition to using the urinal two times per day. Both males and females will use the bathroom faucets three times each day and the kitchen sink once for 15 s each. The following section will discuss the various types of water-efficient fixtures on the market.

A retention pond essentially consists of a body of water that is used to collect storm water runoff for the purpose of controlling the release of this runoff. They have no outlets or streams, creek ditches, etc., and after the water collects, it is then released through atmospheric phenomenon such as evaporation or infiltration. Moreover, retention ponds differ from detention ponds in that a detention pond has an outlet such as a pipe to discharge the water to a stream. A detention pond is similar to a retention pond in that it is a body of water that is used to collect storm water runoff for the purpose of controlling the release of this runoff. However, the pipe that a detention pond contains is sized to control the release rate of the storm water runoff. Although neighborhood ponds serve several purposes, none of these include swimming or wading.

It is important that the pond is of sufficient depth (at least 8–10 feet) to prevent stagnation and algae growth, and to handle the amount of stormwater runoff that is expected to enter it. Most ponds typically have a “safety ledge” at the edge to keep those who unintentionally enter the pond from getting into deep water immediately. This safety ledge is generally no wider than 10 feet and leads directly to much deeper water. The slope off the safety ledge varies greatly, as does the depth of water it leads to. A typical problem that is encountered with ponds is the buildup of bacteria like Escherichia coli. Because of the limited water flow and the tendency of wildlife like geese to gather around ponds, they can become breeding grounds for dangerous bacteria. With proper design and maintenance, ponds can be very attractive, but it may require extra planning and more land. It should be noted that some years ago, most detention ponds were nothing more than ugly holes in the ground hidden as far from view as possible. Today, most developers are attempting to incorporate their detention ponds as amenities, whether they have a permanent pool, walking trails, picnic areas, or playgrounds, and so forth. Indeed, ponds today have become less a “waste of land” and more a beneficial use of land, but without maintenance, these ponds can still turn into major liabilities.

Local requirements for rainwater harvest and wastewater treatment will vary from location to location and jurisdiction to jurisdiction, which is why early involvement and input from local code officials is important. The owner should assemble an experienced team, including the architect, landscape architect, civil and plumbing engineers, and rainwater system designer, early in the design process, if realistic efficiency cost-effective goals are to be achieved. Developers will often try to do away with retention ponds and replace them with pervious concrete pavement which while perhaps more expensive than typical concrete pavement, the cost can be partially or fully offset by reducing or eliminating the need for drainage systems and retention ponds and their associated maintenance costs. In addition to the cost savings, elimination of retention ponds can also help meet the goal of reducing site disturbance found in LEED and therefore help earn additional LEED points. Whether it is practical to incorporate detention ponds or not will depend largely on site development, not large-scale land development. Costs of building a detention versus traditional detention should be studied, bearing in mind that the same storage volume will have to be provided. Then, after adding the cost for pumps, controls, additional storage, and thousands of linear feet of pipe, the decision needs to be made whether all that extra cost outweigh the cost of losing say, 12–15% of your land for a traditional detention pond. Historically, this water was conveniently forced into the city storm drains or into retention ponds, thus becoming someone else’s problem. Water from rainstorms and snowmelt needs to be carefully managed to conserve water in time of need, to better clean water before it starts its journey back to local aquifers, and to lessen the burden of excessive water runoff on municipal system drainage systems.

A system of interlocking, porous pavers resting on a multilayer bed of crushed stones and gravel of different sizes can be used for the parking area. This will allow water to diffuse through the surface of the parking lot, slowing the rush of water into the ground, and permitting the surrounding landscaping to absorb the water while being diverted toward bioswales surrounding the property. Bioswales are gently sloped areas of the property designed to collect silt and other rainwater runoff while slowing down the speed with which water collects (Fig. 8.4). The swales are designed so that water is diverted in a manner so as not to encourage erosion of the ground and soil. The planting of native vegetation in the bioswale can facilitate water absorption, and lengthy root systems can help prevent soil erosion while needing minimum maintenance. The advantage of native plants is that they are hearty and can manage well during periods of dry, hot weather, yet manage to make use of and manage the flow of water from unexpected storms. This ability to combine nature with a well planned surface system can make for an attractive design in addition to being an extremely efficient source of water management and filtering.