Before we get into implementing any plans to cut down the water waste, the first step is to look at the usage for the last 12 months.

  1. WATER AUDIT

The average water used by apartment buildings per unit is as follows:

Per Unit

  • First Resident 75 gallons/day
  • Second Resident 35 gallons/day
  • Third Resident 25 gallons/day

So for a 20-unit apartment complex:

  • Five – Studios 1 Resident 75 gallons/day x 5 = 375 gallons/day
  • One – 1 Bedroom 2 Residents 110 gallons/day x 10 = 1,100 gallons/day
  • Five – 2 Bedroom 3 Residents 135 gallons/day x 5 = 675 gallons/day

TOTAL 2,150 gallons/day

For one month = 2,150 x 30 64,500 gallons/month

Most of the cities in Minnesota charge by 1,000 gallons or 100 cubic feet (7.48 gallons/cubic foot.) The average cost in metro Minnesota is $6.00/1,000 gallons for water and sewer.

The cost for 20-unit apartment building should be: 64.5 x 6 = $387.00 for 20 units or $19.35/unit

This average usage can be reduced by 25 – 30%.

Now you can compare this with your actual usage and see where you stand.

 

  1. WATER PRESSURE AT THE BUILDING

The pressure required at plumbing fixtures from sink, dishwasher, toilet, shower varies from 8 psi – 20 psi.

Pressure at the water meter to supply the farthest and highest fixture during peak demand usually 50 psi pressure is enough to handle a 3-story apartment building. You lose 1 lb of pressure for every 2.31-foot rise; so for 30’ rise you lose 13 psi of pressure.

You should check the water pressure at the meter. Over 60 psi pressure, you should consider lowering the pressure with pressure reducing valve.

The water flow is twice at 150 psi compared to 50 psi.

The water flow is 33% higher at 100 psi compared to 50 psi.

 

3. RECOMMENDED FLOW FOR PLUMBING FIXTURES

Toilet —————-1.6 gallons per flushing cycle

Showerhead ——–2.0 – 2.5 gpm

Lav Faucet———-1.5 gpm

Kitchen Sink——–1.5 gpm

 

  1. FIXTURE MAINTENANCE

• Check for leaky faucets.

• Check for leaky toilets.

Problem with a toilet: Put food coloring in the tank and don’t flush the toilet. If the color runs through the bowl, then your flapper is not sitting over the opening and water is seeping from the tank – Replace the flapper.

• Check for leaky diverters. For tub/shower combination (replace O ring if leaking.)

 

5. COST OF WATER/SEWER IN METRO MINNESOTA

City of Hopkins—————$5.30 / 1,000 gallons

City of Eden Prairie———-$3.98 / 1,000 gallons

City of New Hope————$8.60 / 1,000 gallons

City of Roseville————–$5.35 / 1,000 gallons

City of St. Paul —————$7.30 / 1,000 gallons

City of Minneapolis———-$6.64 / 1,000 gallons

 

WISH YOU HAPPY WATERWISE MANAGEMENT!

Satya Garg graduated from the University of Minnesota in 1968 with an MS in Mechanical Engineering. He is a registered Professional Mechanical and Electrical Engineer in Minnesota. Prior to starting SM Engineering in 1982, Mr. Garg was Manager of Engineering for Planmark, a subsidiary of Super Valu Stores. After graduating from University of Minnesota, Mr. Garg started his career with “Michand Cooley, Hallberg, Erickson & Associates”, one of the most reputed consulting company in Minnesota. He had the opportunity to work with Robert Michand on many interesting projects such as Target stores, conceptual design of mechanical systems for IDS center and troubleshooting HVAC systems at IDS tower. Find him on Google+