WellMate Composite Pressure Tanks for Wells

Pentair Fiberglass Tanks That Won't Rust, Leak, or Dent

Steel pressure tanks rust from the inside out. By the time the leak hits the basement floor, the bottom seam has been corroding for years. WellMate composite tanks fix that at the construction level: a polyethylene inner liner, fiberglass-and-epoxy outer shell, polyurethane bladder separating air from water. No steel anywhere.

Cleanflow stocks the Pentair WellMate WM-Series in five capacities from 19.6 to 86 gallons, plus the air cell replacement kit.

Why WellMate Outlasts Steel Pressure Tanks

No corrosion path. Polyethylene liner, fiberglass and epoxy shell, NSF/ANSI 61 listed for potable water.
Less than half the weight of steel. A 47-gallon WM-14WB is roughly 42 lbs vs 90+ lbs for a steel one-person carry down basement stairs.
Serviceable bladder. When the air cell wears (typically 7–15 years), replace just the bladder with the air cell kit, not the whole tank.

Shop WellMate Pressure Tanks by Capacity

Sized by drawdown (usable water between pump cycles), not total tank volume. Standard residential wells run a 30/50 or 40/60 PSI pressure switch.

Small Residential — 1 to 2 People

WellMate WM-6 — 19.6 Gallon, 125 PSI, 1" NPT

The WellMate WM-6 covers small homes, cabins, and outbuildings on a 1/2 HP pump. ~6.7 gallons drawdown at 30/50, 1" Quick Connect.

Standard Residential — 2 to 6 People

WellMate WM-9 — 29.5 Gallon, 125 PSI, 1" NPT

The WellMate WM-9 is the workhorse for most homes with 2 to 4 people on a 1/2 to 3/4 HP pump, ~10 gallons drawdown.

WellMate WM-12 — 40.3 Gallon, 125 PSI, 1" NPT

The WellMate WM-12 suits 4–6 people with appliances running concurrently. ~14 gallons drawdown, less cycling, longer pump life.

Large Residential and Light Commercial

WellMate WM-14WB — 47 Gallon, 125 PSI, 1-1/4" MNPT

The WellMate WM-14WB moves up to 1-1/4" — 14.1 gallons drawdown, equivalent to a 140-gallon galvanized tank. Right for irrigation, large estates, or duplexes.

WellMate WM-25WB — 86 Gallon, 125 PSI, 1-1/4" MNPT

The WellMate WM-25WB is the largest single-tank option, 25 gallons drawdown, equivalent to a 250-gallon galvanized. Light commercial, multi-family, or high-demand residential.

Replacement Air Cell Kits

WellMate Air Cell Replacement Kit — Universal WM-Series

When the bladder wears out, replace the cell, not the whole tank. The WellMate Air Cell Replacement Kit ships with the butyl air cell, O-rings, and hardware sized to your model (WM-6 through WM-35WB). For newer gray-shell tanks.

WellMate Models At-a-Glance — Compare Specs

Model	Capacity	Drawdown	Connection	Max PSI
WM-6	19.6 gal	~6.7 gal	1" MNPT QC	125
WM-9	29.5 gal	~10 gal	1" MNPT QC	125
WM-12	40.3 gal	~14 gal	1" MNPT QC	125
WM-14WB	47 gal	14.1 gal	1-1/4" MNPT	125
WM-25WB	86 gal	~25 gal	1-1/4" MNPT	125

Note: All WM-Series tanks ship factory pre-charged at 38 PSI. WM-6 through WM-12 use the smaller 1" connection. Check your existing line size before ordering the WM-14WB or WM-25WB.

How to Size Your WellMate Pressure Tank

A pump that cycles less lasts longer. Match drawdown to demand: WM-6 for 1-2 people on 1/2 HP, WM-9 for typical 4-person homes on 3/4 HP, WM-12 for irrigation or 4-6 people. WM-14WB and WM-25WB suit 1 HP and larger pumps.

Set tank pre-charge 2 PSI below pump cut-in 28 PSI for 30/50, 38 PSI for 40/60. Tanks ship pre-charged at 38 PSI; verify with a tire gauge before installation.

Pairs Well With

Building a complete well system? Match your tank with well pumps and pressure tank accessories (tank tees, switches, gauges). For low-pressure feed lines, see booster pumps. Compare brands in the pressure tanks or well pumps and pressure tanks collections.

Buy WellMate Pressure Tanks Online from Cleanflow

Cleanflow ships the full Pentair WellMate WM-Series across Canada and the USA. Add to cart, or contact the team for sizing help. Free shipping on Canadian orders over $199.

Will a WellMate tank fit my existing well system?

Yes, in most cases. WM-6, WM-9, and WM-12 use 1" MNPT Quick Connect; WM-14WB and WM-25WB use 1-1/4" MNPT. A standard tank tee adapts to your existing pump line, pressure switch, and gauge.

How long do WellMate composite tanks last?

The fiberglass shell lasts the lifetime of the installation. There's no rust failure mode. The internal bladder typically lasts 7 to 15 years before getting replaced with the air cell kit.

What pre-charge pressure should I set?

Set the tank pre-charge 2 PSI below the pump's cut-in pressure, 28 PSI for a 30/50 switch, 38 PSI for a 40/60. Verify with a tire gauge before installation.

Are WellMate tanks safe for drinking water?

Yes. The polyethylene inner liner and epoxy-resin shell are NSF/ANSI 61 listed for potable water. All materials meet U.S. drinking water requirements with no lead-bearing brass on water-contact surfaces.

What's the warranty on WellMate pressure tanks?

Pentair backs WellMate tanks with a 5-year limited warranty for residential potable water installations and 2 years for non-residential use. The warranty covers manufacturing defects in the shell and bladder.