Hydraulic Calculators

Engineering-Led Sizing · Watermain Supply · Houston, TX

Hydraulic CalculatorsPump, Tank and Well Sizing Tools

Five free calculators that turn what you can count and measure — fixtures, well depth, elevation, sun hours — into the flow, the head and the equipment the job needs.

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Every pump question comes down to two numbers: how much water, in gallons per minute, and how hard the pump has to push it, the total dynamic head in feet. Get those right and the pump, the tank and the controls follow. Get them wrong and even the best pump short-cycles, starves or burns out. Each calculator below works those numbers out for one kind of job and shows the reasoning, so you can check it.

Not sure which one fits? Call 1-888.510.4036 or email sales@watermainsupply.com. All products are genuine, factory-new equipment in original manufacturer packaging, sold and supported by Watermain Supply, an independent industrial supplier.

Pick Your Calculator

Start with where the water comes from and where it goes.

Booster Pump Sizing

Peak GPMBoost PSITankModel Check

Works out the peak flow from the building's fixtures, the boost pressure the supply is missing and the pressure tank, then checks booster models against the duty.

Use it whenCity or tank water arrives with too little pressure: homes, multi-story buildings, commercial and light industrial.
Open the Calculator

Pressure Tank Sizing

DrawdownTank VolumePrecharge

Works out the tank size for your pump flow, pressure switch setting and minimum run time, so the pump rests between starts instead of cycling itself to death.

Use it whenReplacing a waterlogged tank, adding a larger pump, or the pump clicks on and off every few seconds.
Open the Calculator

Well & Irrigation Pump Sizing

FlowLiftSwitch SettingPump Type

Works out the flow, the lift and the pressure for jet pumps on shallow and deep wells, and for sprinkler and irrigation pumps.

Use it whenThe pump sits above ground: a jet pump in the well house or a sprinkler pump on a lake or shallow well.
Open the Calculator

Submersible Well Pump Sizing

GPM ClassHP2 or 3-WireParts List

Works out the flow, total head, motor size, wiring, pressure tank, setting depth and a full parts list for 3 in and 4 in wells. Print it on one page or send it to us.

Use it whenThe pump goes down the well: homes, ranches, irrigation and light commercial buildings.
Open the Calculator

Solar Water Pump Sizing

Gallons a DayArray WattsTankModel

Works out the daily water, the head, the solar array and the storage tank, then reads the Grundfos curves for the SQFlex or CRFlex model that covers it. Print it or send it to us.

Use it whenThere is no power line at the well, pond or tank: stock water, remote homes, off-grid irrigation.
Open the Calculator

New to Pump Sizing?

FlowHeadPump Curves

Pump Curve 101 explains flow, head and how to read a pump curve in plain English. It makes every result page on these calculators easier to read.

Start here whenThe words on a pump listing or a result page are new to you.
Read Pump Curve 101

Four Numbers That Make a Good Answer

The calculators are only as good as what goes in. These are the ones people most often guess.

The pumping water level

Static level plus drawdown, from the driller's log or a test. The pump lifts from there, not from the static level.

The elevation

From the pump or wellhead up to the house, the top floor or the tank inlet. Every 2.31 ft is 1 PSI the pump has to make.

The real fixture count

Count what is plumbed: bathrooms, kitchens, washers, hose bibs, restrooms. Peak demand comes from fixtures, not floor area.

The power at the pump

115 V, 230 V or three-phase, and how far from the panel. It decides the motor, the wiring and the wire size.

Why Size It With Watermain Supply

We are an independent industrial supplier based in Houston, Texas, selling pumps and waterworks products nationwide. The calculators are how we start most jobs; a person finishes them.

Engineering-led sizing

Every sizing you send us is checked against the manufacturer's curves and data before we quote, not just matched to a part number.

Several brands, one straight answer

We sell pumps from A.Y. McDonald, DAB, Franklin Electric, Grundfos, Goulds and more, so we recommend what fits the job instead of the one brand on the shelf.

Submittals and documentation

Data sheets, curves and drawings on most listings, and submittals for engineers and contractors on request.

Real people, real hours

Call 1-888.510.4036, Monday to Friday, 8 AM to 5 PM Central, and talk to someone who sizes pumps.

Rather have us size it?Send the driller's log, the building and the power to sales@watermainsupply.com and we come back with the equipment, the reasoning and a quote.

Shop the Main Lines

Sized it already? Go straight to the collection.

Booster Pumps

Residential, commercial and variable-speed pressure boosting systems.

Shop Boosters →

Submersible Pump Systems

Submersible well pumps, pump ends, motors and controls.

Shop Submersibles →

Jet Pumps

Shallow-well, deep-well and convertible jet pumps for homes and cabins.

Shop Jet Pumps →

Irrigation Pumps

Self-priming sprinkler and transfer pumps for lawns, fields and ponds.

Shop Irrigation →

Pressure Tanks

Diaphragm tanks for well and booster systems, 2 to 119 gal.

Shop Tanks →

Ready to Size It

Pick a calculator above, or send us what you know — the well, the building, the power — and we come back with the equipment and a quote.

Call 1-888.510.4036Email a Sizing RequestRequest a Quote
Watermain Supply · Houston, Texas · 1-888.510.4036 · sales@watermainsupply.com · Free shipping on orders of $500 and above
Calculator results are estimates, not a selection; confirm against the manufacturer's current data before specifying.
A.Y. McDonald, DAB, Franklin Electric, Goulds, Grundfos, SQFlex and CRFlex are trademarks of their respective owners, used here for product identification only.
Watermain Supply is a DBA of E4 Industrial LLC, an independent industrial supplier based in Houston, Texas.