Water Efficiency and Management
for Commercial Buildings
Massachusetts Water Resources Authority
The MWRA's Industrial, Commercial and Institutional (ICI) Water Management program was developed to help businesses, industries and institutions improve their water efficiency. Since its formation in 1989, the ICI program has produced surveys and water efficiency plans for six commercial buildings and held over a dozen workshops to assist other commercial building managers. The facilities studied were office buildings with sizes ranging from 145,000 square feet to 1.5 million square feet and annual water usage ranging from 3 million gallons to 43 million gallons.
The graph below shows Average Water Use by Function at facilities studied:
Listed on the following pages are some water efficiency suggestions and examples of applications in typical facilities studied throughout the MWRA service area. Water and sewer rates, as well as cost/savings paybacks, are based on 1994 figures for all examples.
Important Note: Before implementing any water efficiency measure be sure to follow all rules and regulations regarding public health and safety requirements and the Massachusetts Plumbing Code. Be aware that 360 CMR (MWRA sewer use regulations) prohibits the discharge of once-through cooling water to the Authority Sewerage System.
- Install water saving aerators or spring loaded valves on all faucets.
- Install water saving shower heads.
- Retrofit flushometer toilets and urinals with low consumption valve replacement kits.
- Replace existing higher consumption toilets and urinals with Massachusetts Plumbing Code conforming Ultra Low Flush (ULF) toilets and urinals which use 1.6 gallons per flush (gpf) and 1.0 gpf respectively.
- If only replacing a limited number of toilets, replace heavily used fixtures located in high traffic areas first.
- When remodeling, such as for ADA compliance, replace fixtures with ULF models.
One Boston facility took advantage of renovations to the building to replace 126 existing 3.5 gpf toilets with 1.6 gpf toilets. When completed, the change will reduce total water use by 15%. With an implementation cost of $32,000 and estimated annual savings of $22,800, payback occurs in 1.4 years.
By installing 30 faucet aerators, a commercial building in Brookline could reduce water consumption by 190,000 gallons per year. The cost of the devices and labor is approximately $300 and the savings for the retrofit are estimated at $1,250 per year -- a payback of 2 months.
HEATING AND COOLING
- Avoid excessive cooling tower blowdown, check with chemical vendor to increase concentration ratio of cooling tower.
- Make-up water and blowdown should be submetered and recorded regularly to address any anomalous usage patterns that could indicate leaks or problems in the system.
- Discuss cooling tower sewer abatement with your city/town water department.
- Utilize sidestream filtration to reduce concentration of solids.
- Investigate possibility of steam condensate for cooling tower make-up.
- Consider ozone treatment for cooling tower.
- Check steam traps and ensure return of steam condensate to boiler for reuse.
- Limit boiler blowdown, check continuous blowdown systems and adjust if necessary.
- Minimize the water used in cooling equipment, such as compressors, in accordance with manufacturer's recommendations. Utilize solenoid controls and timers to match cooling water to duty cycle of equipment.
- Employ an expansion tank for boiler blowdown drainage rather than cold water mixing.
- Replace water-cooled equipment with air-cooled units where possible and economically feasible.
By incorporating a once-through A/C condenser into the existing chilled water loop, a downtown Boston facility can save an estimated 460,000 gallons of water per year, netting $3,000 annually. The implementation cost for this measure is $1,800 resulting in a payback of 7 months.
RESTAURANT KITCHENS AND CAFETERIAS
- Operate dishwashers with full loads only, ensure that water shuts off when no ware is in the washer.
- Reduce flow of water to minimum necessary in scrapper troughs, food prep, wash down and frozen food thawing.
- Install high pressure/low flow spray rinsers with automatic shut off for pot washing.
- Adjust ice machines to dispense less ice if excess ice is produced.
- Control flow of water to garbage disposer or consider eliminating the use of the disposer altogether.
- Retrofit once-through water-cooled refrigeration and ice machines and incorporate into recirculating cooling loop wherever possible.
- Consider life cycle costing and replacement of water using equipment such as dishwashers, refrigeration units and ice machines with water efficient and air-cooled models.
Another Boston building reduced their total water consumption by 10% by eliminating once-through cooling of 2 ice machines and connecting them to the available condenser water loop. The implementation cost was $1,475 and the projected annual savings of $5,680 yields a payback of 3 months.
A Back Bay office building reduced the flow of its scrapper trough from 24 gpm to 6 gpm with flow limiting devices giving a projected annual water savings of 1.1 million gallons. The water and sewer cost savings is estimated at $8,500 and the cost to implement the measure was approximately $200, the payback - 2 weeks.
- Read water meters and submeter all major water using systems. Graph and analyze data to spot trends that could indicate leaks or malfunctioning equipment.
- Locate and repair leaks. Develop a regular maintenance schedule and fix leaks immediately.
- Check solenoid valves and switches on all water-using equipment periodically; repair or replace as necessary.
- Maintain insulation on hot water pipes.
- Replace any water-using equipment or fixtures that wear out with water-saving models or air-cooled units where possible.
Make presentations to financial decision makers
- Know your water and water related costs and present information with numbers showing costs and savings accrued over a ten year period.
- Present information in financial language.
- Show current water and sewer costs and compare with other utility costs.
- Discuss life cycle costing for equipment replacement.
- Implement measures in phases and develop budgeting plans for each task.
- Chart and graph progress and show dollar savings for implemented measures.
Initiate employee awareness and input
- Offer incentives for successful ideas for saving water.
- Post information on changes made and seek feedback.
Encourage water conservation
- Increase public awareness with bathroom mirror stickers and brochures with water saving ideas (available from the MWRA).
- Post signs showing your building-wide commitment to saving water.
- Encourage water conservation at home as well.
Develop a water management plan
- Delegate responsibility for actions, involve management of areas such as kitchens.
- Make and meet environmental goals to save energy and water and promote a "green" image for your facility.
- Chart progress and post results.
***A leaking faucet can waste up to 1000 gallons of water a week - that's over $300 per year lost.***
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