Overview
One of the simplest ways to conserve water is to upgrade water-using appliances. |
In this section, we focused on specific water-saving appliances such as toilets, urinals and showerheads, and we analyzed appliances and fixtures currently used by the University of Houston in order to make appropriate recommendations based on our findings. Minor adjustments – specifically in on-campus restroom urinals and shower heads – can save significant amounts of water, operational costs and maintenance time.
Reducing indoor water use can also be accomplished through water-efficiency standards for plumbing fixtures. Generally, the standards impose a maximum on the amount of water used per flush by toilets and urinals and per minute by faucets and shower heads. In the United States, these amounts or flow rates are described as gallon per flush (gpf) or gallon per minute (gpm). Efficiency standards also typically leave it to fixture manufacturers to meet these goals without compromising performance. According to the National Conference of State Legislatures, the standards can also apply to the sale and installation of plumbing fixtures in addition to their manufacture (33). Today, nine states have their own mandatory standards for plumbing fixtures while others are using financial incentives, community planning efforts, and water conservation requirements for public buildings to promote the adoption of efficient fixtures (See Fig. 1). |
The federal government enacted national standards in a comprehensive legislation called the U.S. Energy Policy Act of 1992 (EPAct 1992), which set minimum efficiency standards for all toilets, showers, urinals and faucets manufactured in the United States after 1994.
In 2006, the U.S. Environmental Protection Agency (EPA) created the WaterSense Program, a voluntary national program that certifies products that use 20 percent less water than the federal minimum without sacrificing performance. WaterSense certified fixtures include dual-flush toilets and 1.28 gpf toilets, which are lower than the federal maximum flow rate of 1.6 gpf. Since then, California, Georgia, Texas, and most recently Colorado have matched the EPA WaterSense flow rate criteria in creating their state efficiency standards (33). |
Toilets
Toilet fixture replacement has been a staple initiative to reduce potable water consumption since the late 1980's. In contrast to older models of gravity-assisted toilets manufactured prior to 1980 – which, on average, use six gallons of water per flush – two distinct types of toilet fixtures dominate the market today:
ULFTs are defined by an effective flush volume in the range between 1.28-gallons per flush (gpf) and 1.6-gpf. HETs use 1.28-gpf or less (34).
- ULFTs (Ultra-Low Flush Toilets) and
- HETs (High-Efficiency Toilets).
ULFTs are defined by an effective flush volume in the range between 1.28-gallons per flush (gpf) and 1.6-gpf. HETs use 1.28-gpf or less (34).
According to the EPA, if all older, inefficient toilets in the United States were replaced with WaterSense labeled toilets, 520 billion gallons of water could be saved each year. Replacing a traditional non-efficient toilet with an ULFT can save 38 gallons per day, adding up to 19,000 gallons per year per toilet; replacing a traditional non-efficient toilet with a HET can save 45 gallons a day and 23,000 gallons per year per toilet (34).
Currently, the toilet fixtures at the University of Houston are low-flow units, which use only 1.28 gpf and meet federal policy requirements. |
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Urinals
Conventional urinals use between one to three gallons of water per flush, and at the University of Houston they use about 1.1 gpf. Thus, we recommend replacing conventional urinals with waterless versions in order to yield significant water savings and costs of sewage treatment and pumping power (35).
How It Works
While conventional flush urinal fixtures have a water-filled trap that prevents sewer gas from rising through the pipes, most waterless urinals utilize proprietary sealant liquids that act as a vapor trap. The liquids are composed primarily of oils or alcohols that are lighter than water, and urine passes through this liquid and flows down the drain. The sealant liquid, except for a tiny amount carried down the drain with each use, remains in place to trap odors and prevent them from entering the restroom.
CostsInitial costs for waterless urinals vary depending on the price of the fixtures and the price of installation. Annual costs for servicing waterless urinals vary depending on need, price, and longevity of replaceable cartridge traps. In a workplace with 1,000 men, annual maintenance costs range from approximately $1,200 to $4,700. According to the U.S. Army Engineer Research and Development Center, simple payback time typically ranges from half a year to three years for new installation and retrofit with waterless urinals (35).
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Savings
In new construction, up-front savings can result from eliminating water supply lines, flush valves, sensors and drainage hook up charges. To put this into perspective, in a workplace with 1,000 men, replacing conventional urinals with waterless urinals would result in savings of approximately 1.56 million gallons annually, and an estimated $21,000 in water and sewer costs.
We analyzed a study conducted by Waterless Co. which concluded that a typical office building restroom with three urinals and 120 men equals a yearly water use of 237,600 gallons of potable water flushed down the drain. This assumes three uses per person per day and only 220 working days (36). Base on this information, we calculated annual savings on a large university scale and highlighted our process below:
We analyzed a study conducted by Waterless Co. which concluded that a typical office building restroom with three urinals and 120 men equals a yearly water use of 237,600 gallons of potable water flushed down the drain. This assumes three uses per person per day and only 220 working days (36). Base on this information, we calculated annual savings on a large university scale and highlighted our process below:
- For every three conventional urinals replaced with waterless versions, the university would save an average of $983.55 (excluding labor costs and the initial appliance cost of $750). Thus, the university will only gain $233.55 the first initial year, but after two years, it would gain annual savings amounting to $983.55.
- Taking this information a step further, if we knew the exact number of urinals at UH, we can calculate the total annual savings. Below were the steps taken to find this calculation:
- Divide the total number of urinals by three
- Multiply the quotient by the total yearly water savings (237,000 gallons)
- Divide the product by 1000
- Multiply the quotient by the price per 1000 gallons ($4.20)
Showerheads
According to the Energy Policy Act of 1992, the national efficiency standard for showerheads is 2.5 gpm at 80 pounds per square inch (psi) (33). A total of 68 showerheads at the University of Houston’s Moody Towers dormitory building use two gallons per minute (gpm) each. After researching various models from different showerhead producing companies, we discovered an affordable, low-flow, 1.25 gpm showerhead from Niagara Earth that meets national efficiency standards and our on-campus water conservation requirements.
In order to calculate the total annual savings from the replacement of existing showerheads with low-flow, 1.25 gpm versions, we considered the following factors:
In order to calculate the total annual savings from the replacement of existing showerheads with low-flow, 1.25 gpm versions, we considered the following factors:
- Cost of each shower head - $5.25
- Total number of residents at Moody Towers – 550 students
- Average shower time – 8 minutes
- Cost per 1000 gallons of water - $4.20
Based on these factors, we discovered that each dormitory building uses 3,212,000 gallons. Replacing existing showerheads with water-efficient versions will save 1,204,500 gallons per year. For the first year, we included the initial appliance cost ($357) with the annual water cost ($8,331.13) to bring a total water utility bill of $8,688.13 and savings of $4641.68. After the second year, we would annually pay $8,331.13 and save about $4,998.68.
Funding
The monetary savings the university will gain after replacing conventional appliances with energy-efficient versions will offset initial costs over time. The initial costs include the cost of appliances excluding installation fees. The university would minimize labor fees by having current Facilities Services staff (rather than service company workers) install the appliances.
Additionally, the replacement of appliances would be a long term initiative. Rather than paying a large sum one time, the university can purchase a specific amount each year and gradually make the switch over time. Based on our recommendations, after the second year, the university would save $4,998.68 from installing low-flow showerheads in one dormitory building and $983.55 for replacing three conventional urinals with waterless ones. Total annual savings amount to $5,982.23 for making minor adjustments, which will result in significant savings in energy and water costs in the future.
Additionally, the replacement of appliances would be a long term initiative. Rather than paying a large sum one time, the university can purchase a specific amount each year and gradually make the switch over time. Based on our recommendations, after the second year, the university would save $4,998.68 from installing low-flow showerheads in one dormitory building and $983.55 for replacing three conventional urinals with waterless ones. Total annual savings amount to $5,982.23 for making minor adjustments, which will result in significant savings in energy and water costs in the future.