Well Pressure Switch 30/50 vs 40/60: Which to Use

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Quick answer from a licensed plumber: The numbers are the pump’s on and off pressures. A 30/50 switch starts the pump at 30 psi and stops it at 50; a 40/60 switch runs from 40 to 60. The higher band gives more pressure at the taps, but three things change with it: the tank precharge (Amtrol’s rule is 2 psi below cut-in, so 38 psi instead of 28), the water delivered per cycle (Amtrol lists 5.4 instead of 6.2 gallons for a 20-gallon WX-202), and the pressure the pump must reach. The switch has live wiring inside, so the change is a licensed pro’s job.

Replacing a failed 30/50 switch? Match the setting printed on the old one. See the Eastman 60043 (30/50) on Amazon (the Square D 9013FSG2J21 we used to link was third-party seller only on 10/3/2026)

What the Two Numbers Mean

The first number is the cut-in pressure, where the switch starts the pump. The second is the cut-out pressure, where it stops the pump. Amtrol describes the cycle from the tank side: as the pump fills the tank, “the air above the diaphragm is compressed. This increases the pressure in the tank and causes the pressure switch to turn off the pump,” and when water is used, “The reduced pressure starts the pump and refills the tank.”

So a 30/50 switch holds the house between 30 and 50 psi, and a 40/60 switch between 40 and 60. Both are a 20-psi band; the 40/60 band is simply 10 psi higher.

30/50 vs 40/60 Side by Side

Drawdown is Amtrol’s term for “The amount of water delivered between pump cycles.” The same tank delivers less water per cycle at the higher setting, so the pump starts more often unless the tank is larger. Our well tank model number guide decodes the WX, CH and PL sizes.

Should You Move from 30/50 to 40/60?

The higher band gives stronger pressure at the fixtures. Before anyone changes it, three things have to check out:

1. The pump has to reach the new cut-out. A pump that cannot build 60 psi will run and never shut off. Output falls as pressure rises: Wayne’s performance chart for its 1/2 hp CWS50 jet pump, at a 30-foot well depth, lists 363 at 30 psi, 280 at 40 psi and 196 at 50 psi (same units in each row). Wayne’s CWS manual lists “CUT IN PRESSURE 30 PSI” and “CUT OUT PRESSURE 50 PSI,” and its replacement part is a “30/50 Pressure Switch Kit 64031-WYN1.” Check your own pump’s chart first; our shallow well pump comparison lists flow at 50 and 60 psi for two common pumps.
2. The tank precharge has to move with it. Amtrol: set the precharge “2 psig below the pressure switch pump cut-in setting. (Example, 38 psig precharge for a 40/60 pressure.)” Amtrol also says only licensed professionals should check or adjust it, and never to add air to a tank that has lost air, shows corrosion or has shorter pump cycles than when new, because that “can mean there may be internal corrosion.”
3. The tank has to be big enough. On Amtrol’s quick sizing table, a 10 gpm pump up to 3/4 hp calls for a WX-203 at 30/50 but a WX-250 at 40/60. Our well pressure tank size chart has Amtrol’s full table.

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Replacing a Failed Switch: Match the Setting

If the switch has failed and nothing else about the system is changing, replace it with the same setting that is printed on it. Examples from the makers and listings we read:

• Square D Pumptrol 9013FSG2J21, 30/50. Its Amazon listing gives a “30-50 psi pressure setting,” a “cut-out range of 20-65 psi,” an “adjustable differential range of 15-30 psi,” and says it “works with a 1. 5 hp or less pump,” with a “1/4″ NPSF internal fluid connection.”
• Square D FSG2J24CP, 40/60. Its Amazon listing is titled “Square D FSG2J24CP 40 To 60 PSI Water Pump Pressure Switch.”
• Superior Pump 99243, 30/50. Superior describes it as a “Universal replacement pump switch for pumps with 1/4 in. NPT connection.”
• Wayne CWS jet pumps. Wayne lists its own “30/50 Pressure Switch Kit 64031-WYN1 (ALL MODELS).”

What You Can Safely Check Yourself

If the system has a pressure gauge, watch it through one full cycle: open a faucet and note the pressure when the pump starts, then close it and note where the pump stops. Those two readings should sit near the numbers on the switch. For a pump that starts and stops too often, Wayne’s troubleshooting chart lists “Incorrect tank pressure (pre-charged tank),” a “Ruptured disphragm/bladder,” a “Leak in house piping,” a “Foot valve or check valve stuck open,” or an “Improperly adjusted or damage pressure switch.”

Replacement Switches in Stock on Amazon

For the licensed pro doing the swap, or to have on hand. The Square D 9013FSG2J21 (30/50) and FSG2J24CP (40/60) we used to link were sold only by third-party sellers on 10/3/2026, so they are not linked. These two were in stock on October 3, 2026:

• 30/50: Eastman 60043 pressure switch, sold by Amazon; the listing gives it a 30-50 psi factory preset and a 1/4-inch FPT connection, for jet, submersible and reciprocating pumps.
• 40/60: Merrill MPSM44060 pressure switch, sold on Amazon by Merrill Manufacturing; the listing gives a 40 psi cut-in, a 60 psi cut-off and a low-pressure cut-off with a manual lever.

FAQ

What does 30/50 mean on a well pressure switch?

The pump turns on when pressure drops to 30 psi (cut-in) and off when it reaches 50 psi (cut-out). A 40/60 switch does the same between 40 and 60 psi.

Is 40/60 better than 30/50 for a well?

It gives about 10 psi more pressure at the fixtures, but the tank precharge has to be raised to 38 psi, each cycle delivers less water from the same tank (Amtrol lists 5.4 vs 6.2 gallons for a WX-202), and the pump must be able to reach 60 psi. Check the pump’s performance chart first. If the swing between cut-in and cut-out is the real complaint, see how a constant pressure well system works instead.

What should the tank pressure be for a 40/60 switch?

Amtrol says to set the precharge 2 psi below cut-in, and gives 38 psi as its example for a 40/60 setting. For 30/50, Wayne’s manual says 28 psi. Amtrol says only licensed professionals should check or adjust the precharge.

Can I change my well pressure switch from 30/50 to 40/60?

Only if the pump can reach 60 psi and the tank precharge is raised to match. Both steps involve the switch’s live electrical terminals and the tank air charge, so have a licensed plumber or electrician do it.

Why does my well pump turn on and off so often?

Wayne’s troubleshooting chart lists incorrect tank pressure, a ruptured diaphragm or bladder, a leak in house piping, a foot valve or check valve stuck open, or an improperly adjusted or damaged pressure switch.

Why Trust Plumbing Picks

Plumbing Picks is written by a licensed Georgia journeyman plumber. Every part number, size, setting and fit on this page comes from the manufacturer pages and documents listed below, which we opened and read; product details come from those makers and from the Amazon listings, not from hands-on testing. Each linked product was new and in stock, sold by Amazon or by the maker’s own store, when we checked on October 3, 2026. Where a link goes to Amazon we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.

Sources

• Amtrol: Well-X-Trol installation and operation instructions (MC10185)
• Amtrol: Well-X-Trol Quick Sizing Guide (MC7025, 03/26)
• Wayne: CWS Series convertible well jet pump manual (640003W-001 E)
• Superior Pump: 99243 30/50 PSI Pressure Switch

Bottom Line

Replace a failed switch with the same setting. Move from 30/50 to 40/60 only if the pump can reach 60 psi, and have the tank precharge raised to 38 psi at the same time. Expect a little less water per cycle from the same tank. Anything inside the switch cover or at the tank air valve is work for a licensed pro.