Buying guide
Choosing Well Pump & Pressure-System Equipment: What to Match Before You Buy
The "best" pump is the one that matches your well. This guide lists what has to match, where to find each number, and which mistakes cost the most.
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Disclosure
We don't earn commissions on anything on this page, and we haven't physically tested any products. This guide is research-based: it's built from manufacturer installation manuals and trade literature. We don't publish "best product" rankings until we can back them with hands-on evidence or a qualified reviewer — here's why and how.
Match the pump to your well, not to a horsepower number: it must fit the casing, deliver the flow you need at your total head (lift + friction + pressure), run on your circuit's voltage, and — for three-wire motors — pair with a matching control box. Then size the tank from the pump's flow, set the switch range the pump can reach, and use check valves suited to the pump type.
Who this guide is for
- Owners comparing a contractor's quote with what they've read.
- Owners replacing a tank or switch and wanting to get the numbers right.
- Anyone about to buy a pump online who isn't sure it will fit.
Pump selection and installation on submersible systems is professional work. Knowing the specs still helps you ask the right questions and avoid paying for the wrong equipment.
Matching a pump
| Spec | Why it matters | Where to find it |
|---|---|---|
| Pump type | Shallow-well jets are limited to about 25 ft to water; deeper water needs a deep-well jet or a submersible[1] | Well log; water-level measurement |
| Casing diameter | Standard residential submersibles are 4-inch units[2] | Measure at the wellhead; well log |
| Flow at your total head | A pump's rated GPM applies at one head only; flow falls as head rises | Manufacturer pump curve + your pumping level and pressure (1 psi = 2.31 ft)[3] |
| Well yield | A pump that out-pumps the well draws the water to the intake | Driller's yield test or a contractor's measurement |
| Horsepower | Follows from flow and head, not the other way round | Pump curve |
| Voltage and phase | Must match the circuit; supply within 10% of rating[2] | Existing motor label; panel breaker |
| Two-wire or three-wire | Three-wire needs a control box matched to motor HP and voltage[2] | Look for a control box; count conductors (a pro can confirm) |
| Cable size and length | Undersized cable causes voltage drop at start | Manufacturer cable tables — installer's job |
Matching a pressure tank
- Drawdown, not gallons. Size from the pump's flow and minimum run time — see tank sizing or the calculator.
- Maximum working pressure. Amtrol's residential Well-X-Trol line is rated at 150 psig, and a relief valve is required.[4] Check the rating of any tank you consider.
- Space and weight. Measure height and floor space; a full tank is heavy, and Amtrol says the floor must support its operating weight including water.[4]
- Installation terms. Amtrol's manual states its tanks must be installed by a licensed professional and that not following the instructions voids the warranty.[4] Read the warranty before you buy for DIY installation.
Matching a pressure switch and gauge
- Pressure range that your pump can reach with margin: cut-out at least 5 psi below the pump's maximum (Pentair).[5]
- Electrical rating suitable for your motor's horsepower and voltage.
- Low-pressure cutoff if your well has ever run dry — it stops the pump when pressure collapses.
- Gauge range that comfortably exceeds your cut-out so the needle isn't pinned near the top of the dial.
- A new ¼-inch nipple or sensing tube with any new switch.
Check valves and fittings
- Franklin: a check valve within 25 ft of the pump if the pump has none built in; never swing-type check valves on submersibles; only positive-sealing valves.[2]
- For variable-speed (constant-pressure) systems, Franklin recommends check valves designed for variable flow.[2]
- Drain-back or drilled check valves are not a substitute — Franklin says they create upthrust and water hammer problems.[2]
Your equipment worksheet
Fill this in before you shop or call
- Well
- Depth ____ ft · casing ____ in · static level ____ ft · pumping level ____ ft · yield ____ GPM
- Pump
- Type ____ · brand/model ____ · HP ____ · voltage ____ · 2-wire / 3-wire · setting depth ____ ft
- Controls
- Switch ____/____ psi · control box model ____ · pump protection? ____
- Tank
- Brand/model ____ · total volume ____ gal · age ____ · precharge ____ psi
- Demand
- Bathrooms ____ · irrigation? ____ · treatment equipment ____
Where people buy well equipment
Local plumbing and pump supply houses, big-box stores and online retailers all sell well equipment. Supply houses typically stock the brands local contractors service; online listings make it easy to buy a pump that doesn't match your control box or casing. Whatever you buy, check that the warranty survives how it will be installed.
About product recommendations
You'll find plenty of "best well pump" lists online. Google's own guidance for review content asks for first-hand evidence and measurements;[6] a list assembled from product pages can't provide that. When we publish product comparisons, they'll say exactly what was and wasn't tested, and specifications will come from manufacturer documents. Until then, the most useful thing we can offer is this checklist — and the cost guide to check the price.
Sources
- Pentair. Pro Shallow Well Jet Pumps — Installation & Operation Manual (P15001, 2023). Accessed Sept. 28, 2026.
- Franklin Electric. Submersible Motors: Application, Installation & Maintenance (AIM) Manual, 60 Hz. Accessed Sept. 28, 2026.
- Amtrol. Sizing the Well-X-Trol (commercial sizing handbook). Accessed Sept. 28, 2026.
- Amtrol. Well-X-Trol Residential Pre-Pressurized Well Tanks — Installation & Operation Instructions (WX-101 through WX-350). Accessed Sept. 28, 2026.
- Pentair. Adjusting Well Pump Pressure Switches (instruction sheet U80-129). Accessed Sept. 28, 2026.
- Google Search Central. How to write high quality reviews. Accessed Sept. 28, 2026.
We cite manufacturer documentation and public agencies first. Read how we choose and check sources.