Basic assumptions:
For ease of understanding, let’s say water costs 1 cent/gallon. We are also assuming a two-person household, averaging five toilet flushes per person per day, one 10-minute shower per person per day, four loads of laundry per week and 1 minute of running the bath faucet per person per day.

Note: None of these paybacks take into account the energy savings from reduced hot water use. Hot water costs an additional 1 cent per gallon to produce, thus making payback periods even shorter.

Water rates in Asheville and Buncombe County:
• Basic rate: $3.45/CCF (1 CCF = 748 gallons)
• Sewer treatment MSD: $3.51/CCF
• Total cost for a gallon of water: $6.96/CCF or $.009/gallon

Faucet aerator:
Assume the bath faucet is on 1 minute per person per day.

• Standard faucet aerator uses 2.2 gallons/minute.
• Low-flow aerators use as little as .5 gallons/minute.
• Savings from installing a new aerator: 1.7 gallons/minute

• 1.7 gallons/minute X 1 minute/day X 2 people = 3.4 gallons/day
• 3.4 gallons/day X 7 days/week X $.01 = $.24/week or $12.48/year and 1241gallons/year
• With the cost of a faucet aerator at $1 each, the payback period is about four weeks.
• For a household of four people, the payback period is about two weeks.

Showerhead:
Assume one 10-minute shower per person per day.

• Standard showerheads use 2.5 gallons/minute.
• Low-flow showerheads use 1.75 gallons/minute.
• Savings from installing a low-flow showerhead: .75 gallons/minute

• .75 gallons/minute X 10 minutes/day X 2 people = 15 gallons/day
• 15 gallons/day X 30 days/month X $.01 = $4.50/month or $54/year and 5475 gallons/year
• With a new showerhead costing about $5, the payback period is just over one month.
• For a household of 4 people, the payback period is about two weeks.

Toilet:
Assume 10 flushes per day for two people.

• Older toilets use 3.5 gallons/flush.
• New toilets use 1.6 gallons/flush.
• Savings from installing a new toilet: 1.9 gallons/flush

• 1.9 gallons/flush X 5 flushes per day X 2 people = 19 gallons/day
• 19 gallons/day X 365 days/year X $.01 = $69.35/year and 6,935 gallons/year
• With a new toilet costing about $80, the payback period is about 14 months.
• For a household of four people, the payback is about seven months.

• Code toilets use 1.6 gallons/flush.
• Ultra low-flow toilets use 1.1 gallons/flush.
• Savings from installing an ultra low-flow toilet: .5 gallons/flush

• .5 gallons/flush X 5 flushes per day X 2 people = 19 gallons/day
• 5 gallons/day X 365 days/year X $.01 = $18.25/year and 1,825 gallons/year
• With the difference in cost between an ultra low-flow and standard toilet at about $100, the payback period is about 5.5 years.
• For a household of four people, the payback is about two years and three months.

Washing Machine:*
Assume four loads per week for two people.

• Standard washing machines use 33 gallons/load.
• Front-loading Energy Star washing machines use 15 gallons/load.
• Savings from buying a front-loading washer: 18 gallons/load

• 18 gallons/load X 4 loads/week = 72 gallons/week
• 72 gallons/week X 52 week/year X $.01 = $37.44/year and 3744 gallons/year
• With a front-loading Energy Star washer costing $300 more than a standard washer, the payback period is about eight years.
• For a household of four people or eight loads of laundry a week, the payback is four years.

*Source: USEPA consumer calculator spreadsheet