Residential Tank Sizing Calculator

Step 1: Select your preferred unit of measure

Step 2: Calculate Drawdown

  1. GPMLPM
  2. Minutes
  3. Calculate Drawdown
  1. Please enter a number in both 'pump delivery rate' and 'desired minimum pump running time' fields.

  1. We could not calculate your minimum drawdown based on the information you provided. Please make changes to the information as necessary, or supply your own calculated volume below.

  1. GallonsLiters
    *

    If a volume of water needed is greater than the amount calculated on line #3, enter that amount on line #3 in place of the calculated volume.

Step 3: Calculate Drawdown Factor

  1. PSIG / kPa / bar
  2. PSIG / kPa / bar
  3. Calculate Drawdown
  1. Please select your minimum system pressure (both cut-in and cut-out).

  1. We could not calculate your drawdown factor based on the information you provided. Please make changes to the information as necessary, or supply your own estimated drawdown factor below. You may consult our drawdown chart for reference.

  1. *

    In keeping with current industry standards, drawdown factors are based on Boyle’s law. Actual drawdowns will vary depending upon system variables including the accuracy and operation of the pressure switch and gauge, actual precharge pressure, and operating temperature of the system.

Step 4: Calculate Tank Size

  1. There were errors with your form. Please make sure all fields have been filled out correctly.

Based on your entries, we calculated the following:

  • Recommended Model:
  • Minimum Capacity: GallonsLiters

Basic sizing and selection requirements

There are three factors to consider when selecting the proper size WELLMATE for your Water system:

  1. The pump delivery rate in gallons/liters per minute (GPM/LPM)
  2. The recommended minimum running time of the pump
  3. The minimum (cut-in) and maximum (cut-out) system pressure parameters

Once these factors are known, the following calculations will determine, in most cases, the correct model to meet your specifications.

See the complete model and specification list below for other tank options.

Specifications

WM Series Quick Connect Performance Data

Model Number Capacity
gal / liter
Maximum
Operating Pressure
psi / kPa / Bar
Drawdown
30/50 Setting**
gal / liter
Diameter*
inch
/ cm
Overall Height*
inch / cm
Height* inlet/
outlet to floor
inch
/ cm
System
Connection
Assembly Weight*
lb / kg
Pallet
QTY.
WM-4 / WM0060 QC 14.5 / 55 125 / 862 / 8.6 4.5 / 17.0 16 / 41 27.5 / 70 1 3/4 / 4.4 1" male NPT 16.9 / 7.6 9
WM-6 / WM0075 QC 19.8 / 75 125 / 862 / 8.6 6.1 / 34.4 16 / 41 32.5 / 82.5 1 3/4 / 4.4 1" male NPT 20.85 / 9.5 9
WM-9 / WM0120 QC 29.5 / 112 125 / 862 / 8.6 9.1 / 34.4 16 / 41 44.5 / 113 1 3/4 / 4.4 1" male NPT 28.80 /13.0 9
WM-12 / WM0150 QC 40.3 / 153 125 / 862 / 8.6 12.5 / 47.3 16 / 41 57.6 / 146.3 1 3/4 / 4.4 1" male NPT 35.05 /15.9 9
WM-23 / WM0300 QC 79.6 / 301 125 / 862 / 8.6 24.6 / 93.1 21 / 53 62.8 / 159.5 2 1/4 / 5.7 1 1/4" male NPT 71.07 / 32.3 4
WM-14WB / WM0180 QC 47.1 / 178 125 / 862 / 8.6 14.6 / 55.3 21 / 53 42 / 106.7 2 1/4 / 5.7 1 1/4" male NPT 46.27 / 21.0 4
WM-20WB / WM0235 QC 60.0 / 227 125 / 862 / 8.6 18.5 / 70.0 24 / 61 42.3 / 107.3 2 1/4 / 5.7 1 1/4" male NPT 52.87 / 24.0 4
WM-25WB / WM0330 QC 86.7 / 328 125 / 862 / 8.6 26.8 / 101.5 24 / 61 56 / 142.3 2 1/4 / 5.7 1 1/4" male NPT 77.22 / 35.0 4
WM-35WB / WM0450 QC 119.7 / 453 125 / 862 / 8.6 37.0 / 140.1 24 / 61 75 / 190 2 1/4 / 5.7 1 1/4" male NPT 102 / 46.4 N/A

WM Series Classic Performance Data

Model Number Capacity
gal / liter
Maximum
Operating Pressure
psi / kPa / Bar
Drawdown
30/50 Setting**
gal / liter
Diameter*
inch
/ cm
Overall Height*
inch / cm
Height* inlet/
outlet to floor
inch
/ cm
System
Connection
Assembly Weight*
lb / kg
Pallet
QTY.
WM-4 / WM0060 C 14.5 / 55 125 / 862 / 8.6 4.5 / 17.0 16 / 41 26 / 66 1 3/4 / 4.4 1" male NPT 14.5 / 6.6 9
WM-6 / WM0075 C 19.8 / 75 125 / 862 / 8.6 6.1 / 34.4 16 / 41 32 / 81 1 3/4 / 4.4 1" male NPT 17.75 / 8.1 9
WM-9 / WM0120 C 29.5 / 112 125 / 862 / 8.6 9.1 / 34.4 16 / 41 44 / 112 1 3/4 / 4.4 1" male NPT 24.75 /11.2 9
WM-12 / WM0150 C 40.3 / 153 125 / 862 / 8.6 12.5 / 47.3 21 / 53 62 / 157 1 3/4 / 4.4 1" male NPT 65.7 /29.8 9
WM-23 / WM0300 C 79.6 / 301 125 / 862 / 8.6 24.6 / 93.1 21 / 53 41.25 / 105 2 1/4 / 5.7 1 1/4" male NPT 43 / 19.5 4
WM-14WB / WM0180 C 47.1 / 178 125 / 862 / 8.6 14.6 / 55.3 24 / 61 41.5 / 105 2 1/4 / 5.7 1 1/4" male NPT 50 / 22.7 4
WM-20WB / WM0235 C 60.0 / 227 125 / 862 / 8.6 18.5 / 70.0 24 / 61 55 1/4 / 140 2 1/4 / 5.7 1 1/4" male NPT 72.75 / 33.0 4
WM-25WB / WM0330 C 86.7 / 328 125 / 862 / 8.6 26.8 / 101.5 24 / 61 55 1/4 / 140 2 1/4 / 5.7 1 1/4" male NPT 72.75 / 33.0 4
WM-35WB / WM0450 C 119.7 / 453 125 / 862 / 8.6 37.0 / 140.1 24 / 61 74 1/4 / 189 2 1/4 / 5.7 1 1/4" male NPT 102 / 46.4 N/A

Low Profile Classic Quick Connect Performance Data

Model Number Capacity
gal / liter
Maximum
Operating Pressure
psi / kPa / Bar
Drawdown
30/50 Setting**
gal / liter
Diameter*
inch
/ cm
Overall Height*
inch / cm
Height* inlet/
outlet to floor
inch
/ cm
System
Connection
Assembly Weight*
lb / kg
Pallet
QTY.
WM-6LP / WM-LP-075 QC 19.3/ 73 125 / 862 / 8.6 6.0 / 22.7 24/ 61 21 / 53 2 1/4 /5.7 1" male NPT 25.2 / 11.4 8
WM-10LP / WM-LP-130 QC 34.5 / 131 125 / 862 / 8.6 10.7 / 40.5 24 / 61 29.8 /75.7 2 1/4/5.7 1" male NPT 32.85 / 14.9 8

Low Profile Classic Performance Data Performance Data

Model Number Capacity
gal / liter
Maximum
Operating Pressure
psi / kPa / Bar
Drawdown
30/50 Setting**
gal / liter
Diameter*
inch
/ cm
Overall Height*
inch / cm
Height* inlet/
outlet to floor
inch
/ cm
System
Connection
Assembly Weight*
lb / kg
Pallet
QTY.
WM-6LP / WM-LP-075 C 19.3/ 73 125 / 862 / 8.6 5.8 / 21.9 24/ 61 20 1/4 / 51 2 1/4 /5.7 1" male NPT 22.75 / 10.3 8
WM-10LP / WM-LP-130 C 34.5 / 131 125 / 862 / 8.6 10.4 / 39.2 24 / 61 28 /71 2 1/4/5.7 1" male NPT 29.5 / 13.4 8

Note: Maximum external operating temperature 120°F (49°C). Maximum internal operating temperature 100°F (38°C). Minimum operating temperature 40°F (4°C).

* Diameter, height and weight may vary slightly without notice.

** In keeping with current industry standards, drawdown factors are based on Boyle's law. Actual drawdowns will vary depending upon system variables, including the accuracy and operation of the pressure switch and gauge and operating temperature of the system.