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 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 14.5 / 55 125 / 862 / 8.6 4.4 / 16.5 16 / 41 26 / 66 1 3/4 / 4.4 1" male NPT 14.5 / 6.6 9
WM-6 / WM0075 19.8 / 75 125 / 862 / 8.6 5.9 / 22.5 16 / 41 32 / 81 1 3/4 / 4.4 1" male NPT 17.75 / 8.1 9
WM-9 / WM0120 29.5 / 112 125 / 862 / 8.6 8.9 / 33.5 16 / 41 44 / 112 1 3/4 / 4.4 1" male NPT 24.75 /11.2 9
WM-11 / WM0130 QC 35 / 132 125 / 862 / 8.6 10.6 / 40.1 21 / 53 33 / 83.8 2 1/4 / 5.7 1 1/4" male NPT 32 / 14.5 4
WM-12 / WM0150 40.3 / 153 125 / 862 / 8.6 12.1 / 45.8 16 / 41 57 / 145 1 3/4 / 4.4 1" male NPT 30 /13.6 9
WM-23 / WM0300 79.6 / 301 125 / 862 / 8.6 23.8 / 90.4 21 / 53 62 / 157 2 1/4 / 5.7 1 1/4" male NPT 65.7 / 29.8 4
WM-14WB / WM0180 47.1 / 178 125 / 862 / 8.6 14.1 / 53.5 21 / 53 41 1/4 / 105 2 1/4 / 5.7 1 1/4" male NPT 43 / 19.5 4
WM-20WB / WM0235 60.0 / 227 125 / 862 / 8.6 18.0 / 68.1 24 / 61 41 1/2 / 105 2 1/4 / 5.7 1 1/4" male NPT 50 / 22.7 4
WM-25WB / WM0330 86.7 / 328 125 / 862 / 8.6 26.0 / 98.5 24 / 61 55 1/4 / 140 2 1/4 / 5.7 1 1/4" male NPT 72.75 / 33.0 4
WM-35WB / WM0450 119.7 / 453 125 / 862 / 8.6 35.9 / 135.9 24 / 61 74 1/4 / 189 2 1/4 / 5.7 1 1/4" male NPT 95 / 43.1 N/A

Low Profile 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 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 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.