EPA WaterSense: Definition & Certification Guide
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EPA WaterSense is a voluntary EPA certification program that labels plumbing products meeting strict efficiency and performance criteria through independent third-party testing and verification. Launched in 2006, WaterSense mirrors the ENERGY STAR model for energy efficiency — consumers see the label and know the product has been tested to use at least 20 percent less water than the federal standard while delivering equal or better performance.
Program History, ENERGY STAR Model & 7.5 Trillion Gallons Saved
WaterSense was established in 2006 in response to growing concerns about long-term water resource availability and municipal infrastructure capacity. The program structure mirrors ENERGY STAR: EPA develops specifications through a stakeholder process, accredited third-party laboratories perform product testing, and manufacturers that pass earn the right to display the WaterSense label. This independent certification distinguishes WaterSense from self-reported efficiency claims.
The program’s cumulative impact is substantial. The EPA reports that WaterSense-labeled products have helped Americans save over 7.5 trillion gallons of water and more than $175 billion in water and energy bills since the program’s inception. These figures reflect adoption across toilets, faucets, showerheads, irrigation controllers, and new home construction — every product category covered by the program.
Third-party certification laboratories must hold accreditation under ISO 17025, the international standard for testing laboratory competence. Manufacturers submit products to these recognized labs for testing against WaterSense specifications before any label claim is permitted.
WaterSense Certification Criteria: 1.28 gpf, 1.5 gpm, 2.0 gpm & MaP Thresholds
Each WaterSense product category carries specific performance criteria that go beyond flow-rate limits alone.
WaterSense toilets are certified at a maximum of 1.28 gallons per flush — 20 percent below the federal 1.6 gpf standard. Certification also requires a MaP (Maximum Performance) flush score of 350 grams or higher, confirming that waste removal equals or exceeds conventional high-volume models.
WaterSense faucets are limited to 1.5 gallons per minute for lavatory applications, compared to the federal maximum of 2.2 gpm. User satisfaction criteria ensure adequate flow perception at this reduced rate.
WaterSense showerheads must deliver 2.0 gpm or less versus the 2.5 gpm federal standard. Performance testing confirms adequate spray coverage and rinsing capability at the reduced flow.
WaterSense irrigation controllers use local weather data or soil moisture readings to replace timer-based scheduling, reducing outdoor irrigation waste by an average of 20 percent.
WaterSense homes are newly constructed buildings certified to use 30 percent less water than typical new construction through a combination of certified fixtures, efficient hot water delivery design, and landscape water management.
WaterSense Fixture Installation, Utility Rebates & Whole-House Upgrades
Bonded Plumbworks’ standard practice includes recommending and installing WaterSense-certified fixtures during fixture installation and bathroom plumbing projects. Many utilities offer rebate programs specifically for WaterSense-labeled products, and Bonded Plumbworks helps homeowners identify eligible upgrades during kitchen plumbing remodels and whole-house retrofit assessments.
EPA Specification Development, ISO 17025 Lab Accreditation & Code Integration
EPA WaterSense specifications are published as standalone performance criteria, each developed through a public stakeholder process. Certification is performed exclusively by laboratories accredited under ISO 17025. State building codes in many jurisdictions reference WaterSense-labeled fixtures as the compliance pathway for water efficiency provisions in new construction and major renovation permits.
TOTO UltraMax II, Kohler Cimarron, Delta, Moen & Rachio WaterSense Products
Toto manufactures the Drake and UltraMax II WaterSense toilets at 1.28 and 1.0 gpf ratings, both passing 800-gram MaP tests in independent laboratory settings. Kohler offers WaterSense-labeled Wellworth and Cimarron models. Delta and Moen produce WaterSense faucets and showerheads across their residential lines with aerator and laminar-flow designs that meet the 1.5 gpm lavatory standard. Rachio manufactures WaterSense-certified smart irrigation controllers that use local weather data to eliminate unnecessary watering cycles.