Laundry with Harvested Rainwater in Idaho

Using harvested rainwater for laundry in Idaho is a practical way to reduce your water bill and conserve municipal supplies. With 18.9 inches of average annual rainfall, a 1,500-square-foot asphalt shingle roof in Idaho can collect approximately 11,514 gal per year. laundry requires roughly 15 gallons per day per person, year-round. With this setup, rainwater can meet approximately 100.0% of your laundry needs, saving an estimated $43.80 per year.

Annual Harvest 11,514 gal 1,500 sq ft roof
Annual Demand 10,950 gal laundry (2 people)
Demand Met 100.0% of laundry
Rec. Tank 1,000 gal storage capacity

Monthly Supply vs. Demand for Laundry in Idaho

The table below shows how your monthly rainwater harvest compares to laundry demand throughout the year. Green values indicate months where your harvest exceeds demand (surplus water for tank storage), while red values show months where you will draw down your stored reserves. Laundry is a year-round use, so demand remains constant regardless of season. Tank sizing should bridge the gap during your driest months.

Month Harvest (gal) Demand (gal) Balance
January 1,346 930 +416
February 972 840 +132
March 1,121 930 +191
April 1,047 900 +147
May 1,196 930 +266
June 897 900 -3
July 374 930 -556
August 374 930 -556
September 598 900 -302
October 748 930 -182
November 1,346 900 +446
December 1,495 930 +565

Harvest by Roof Size for Laundry

A larger roof collection area directly increases your harvest and the percentage of laundry demand you can meet with rainwater. The table below shows how different roof sizes perform in Idaho for laundry (calculated for 2 people).

Roof Area Annual Harvest Demand Met Rec. Tank Savings/Year
1,000 sq ft 7,675 gal 70.1% 100 gal $30.70
1,500 sq ft 11,514 gal 100.0% 1,000 gal $43.80
2,000 sq ft 15,350 gal 100.0% 1,500 gal $43.80
2,500 sq ft 19,189 gal 100.0% 2,500 gal $43.80

Setting Up Rainwater Harvesting for Laundry in Idaho

Using rainwater for laundry in Idaho offers a unique benefit: rainwater is naturally soft, meaning you can use 30-50% less detergent while achieving the same or better cleaning results. Hard municipal water requires more soap to lather effectively, and mineral deposits can make fabrics stiff and dull over time. A rainwater-fed laundry system requires the same setup as toilet flushing — dedicated non-potable plumbing, a pump-and-pressure system, and sediment plus carbon filtration to remove any debris or tannins that could discolor fabrics. The filtration requirements are slightly higher than for toilet use because you want to protect both your clothing and your washing machine from fine sediment. A first-flush diverter on your collection system is especially important for laundry use to keep water clean.

Metal Roof Upgrade: Laundry in Idaho

Upgrading to a metal roof increases your collection efficiency from 80% (asphalt shingle) to 95%, boosting your annual harvest to 13,672 gal from a 1,500-square-foot roof. This increases your laundry demand coverage to 100.0% and raises annual savings to $43.80. Metal roofs also last 40-70 years compared to 20-30 years for asphalt shingle, and their smooth surface sheds debris more effectively, reducing maintenance on your collection system and improving water quality.

Other Uses for Rainwater in Idaho

Explore how harvested rainwater can serve other needs in Idaho:

Get Your Custom Estimate

Use our Rainwater Harvesting Calculator to enter your exact roof area, material, and combine multiple uses for a comprehensive harvest analysis. See all rainwater harvesting data for Idaho or compare all 50 states.