Water Systems Introduction

Development in Southern California has always been limited by the scarcity of clean, fresh water. In the 1970s and 1980s, responses to drought conditions made the Los Angeles region a leader in water conservation, without constraining economic growth and with little inconvenience to residents. Recently, however, several relatively wet years have reduced public concern - and conservation efforts.

Periods of drought are a certainty in the future, and their severity and duration are predicted to increase, due to climate change caused by human activity. Continued economic and population growth will put additional pressure on finite water supplies.

Why Conserve Water?

Conservation of potable water reduces the need for new supplies and treatment plants, avoiding large capital and operating costs - and their associated taxes. Environmental benefits of water conservation in urban areas such as Santa Monica include less pollution from water and sewage treatment and improved habitat quality in Santa Monica Bay, as well as avoiding the negative impacts of new dam and pipeline construction.

There are other reasons to reduce potable water consumption, notably the need to reduce the energy used to heat water. Heating water is the largest energy consumer in multiple-dwelling buildings in California, and the third-largest energy consumer in all U.S. commercial buildings. It constitutes a large portion of the energy budget for hotels and motels, restaurants and schools. In any building, using less energy translates directly into lower operating costs for building owners and tenants, increased profits for businesses and lower taxes for municipalities.

Most water in California buildings is heated using natural gas, which produces carbon dioxide, the most important contributor to global warming. But carbon dioxide is not the only air emission from water boilers and heaters. Air pollutants from poorly maintained natural gas water heaters and boilers include carbon monoxide, nitrogen oxides, and formaldehyde, as well as other trace pollutants. While electric water heaters do not directly produce air emissions, the generation of electricity used produces these same pollutants, and sulfur oxides as well. All of these contaminants are major contributors to degraded air quality throughout the Los Angeles basin - and have been shown to seriously affect indoor air quality in many buildings.

Direct benefits of water-conserving features to real estate developers include greater appeal to two broad and influential market segments: the environmentally conscious buyer or lessor, and businesses and retirees seeking low building operations and maintenance costs. Buildings with water-conservation features in combination with other "green" design measures have a distinct market advantage over less ecologically responsible buildings, selling and leasing more quickly, and often with a price premium.

Design Strategies

Water conservation in buildings and their sites is both practical and inexpensive, especially when rebates and incentives offered by the City, state and federal governments are considered. However, as in many strategies to reduce ecological impacts, water and water heating energy conservation should be considered early in design, monitored during construction and properly commissioned to ensure their proper installation and operation.

Water-Conserving Fixtures and Appliances

Reducing demand for water is the most effective and economical strategy, and the one to implement first. The easiest and most inexpensive method is to use state-of-the-art water-conserving fixtures, fittings and appliances. Second- and third-generation water-conserving fixtures are much improved over earlier efforts, reducing or eliminating operation and maintenance problems. Efficient fixture costs are competitive, and the City of Santa Monica’s Bay Saver program subsidizes their use.

Graywater Systems

After water-conserving plumbing fixtures, installation of a graywater system to provide irrigation allows a second use of water drained from baths, showers, bathroom sinks and washing machines. This is an effective way to reduce the use of treated potable water. Graywater collection and irrigation systems must be considered early in the design process, since they will affect landscaping design and the size and placement of mechanical spaces. This is especially true for gravity-flow graywater systems, since they must be higher than the irrigation systems they service.

Water-Heating Energy Conservation

Reducing the amount of hot water used also reduces the energy required to heat that water. Water heating energy can be further conserved with little extra cost by insulating piping, recovering waste heat from graywater, and by specifying highly efficient boilers and hot water heaters. Many advances have been made in water heating technology in recent years, including sealed combustion chambers, electronic ignitions and direct-vent condensing boilers. Capital costs for efficient heaters can be greatly reduced by taking advantage of the Federal Environmental Protection Agency Energy Star program.

In Southern California, solar water heating can eliminate the need to use non-renewable energy. Low-temperature unglazed solar water heaters are one of the most inexpensive and well-proven renewable energy technologies, and are very well suited for swimming pools and spas, as well as domestic water preheat and process water systems. Glazed flat-plate collectors can provide the higher temperatures required by service water, and can be very attractive when integrated with the envelope design. Low-interest loans and tax rebates provided by the federal government, and grants and loans from California’s Energy Technologies Advancement Program (ETAP) for solar equipment can help to reduce capital costs of solar systems.

Designs incorporating efficient conventional and solar water heaters or graywater systems should be followed up with testing and commissioning before occupancy, to ensure that they operate as intended, and that building operators are well trained in their use and maintenance. Lack of proper testing, commissioning and training is one of the most common reasons for unsatisfactory performance. However, if systems are installed and operating correctly from the beginning, they typically provide years of service, saving water, energy and money.