WellMate Tank, 40 Gallon 16" x 58"

The Pentair WellMate WM-12 is a 40-gallon composite pressure tank measuring 16" x 58", engineered to bring quiet, corrosion-free performance to private well systems. Unlike traditional steel tanks that can rust from the inside out, WellMate tanks use a tough, seamless composite construction that will never corrode, making them an outstanding long-term choice even for demanding water conditions and humid installation environments.

Composite Advantage

WellMate captive-air tanks store water under pressure behind a flexible air cell, reducing how often your well pump must cycle on and off. Fewer pump starts mean less electrical wear, lower energy use, and steadier pressure at every fixture in the home. Short cycling is a primary cause of premature pump failure, so a properly sized and pre-charged pressure tank like the WM-12 directly protects your pump investment while improving day-to-day comfort.

The lightweight composite shell, weighing just 37 lbs, is far easier to handle and maneuver into place than a comparable steel tank, which simplifies installation in basements, crawl spaces, and tight utility rooms. Its rust-proof body resists the corrosion that eventually claims metal tanks, and the smooth composite exterior also resists the condensation sweating that plagues steel tanks in humid environments, helping keep the surrounding area dry.

• 40-gallon capacity in a 16" x 58" upright composite tank
• Seamless, rust-proof composite construction for long service life
• Captive-air design reduces pump cycling and extends pump life
• Lightweight at 37 lbs for easier handling and installation
• Slim 16" diameter fits space-constrained utility areas
• Trusted Pentair WellMate engineering for well water systems

The 40-gallon capacity in a slim 16" diameter makes the WM-12 a versatile fit for many residential installations where floor space is limited but reliable drawdown is essential. To get the most from the tank, set the air pre-charge to the value recommended for your pump's cut-in pressure before commissioning. For homeowners and installers who want a pressure tank that combines dependable drawdown with a body that will not corrode, the Pentair WellMate WM-12 is a proven solution that delivers years of trouble-free service while keeping household water pressure smooth and consistent. Its combination of rust-proof durability, light weight, and dependable drawdown makes it a standout choice for both new installations and replacements.