If you've ever noticed your shower pressure drop the moment someone turns on a faucet in another room, you've experienced the most common complaint about traditional well systems. A constant pressure system solves that problem completely. Here's how it works and whether it's worth adding to your home.
How a Traditional Well System Works
In a standard well system, your pump runs at full speed whenever it's on. A pressure tank stores pressurized water and a pressure switch controls when the pump kicks on and off — typically between 40 and 60 PSI. When pressure drops to 40 PSI the pump turns on; when it hits 60 PSI the pump shuts off.
The result is that your water pressure is always fluctuating somewhere in that 20 PSI range — and every time the pump cycles on, it draws a surge of electricity and puts wear on the motor.
How a Constant Pressure System Works
A constant pressure system adds a variable frequency drive (VFD) controller — like the Franklin Electric SubDrive Utility or Grundfos CU301 — between your power supply and your pump motor. Instead of running at full speed or not at all, the controller adjusts the pump's speed in real time based on your actual water demand.
Running one faucet? The pump runs slow. Running five fixtures at once? The pump speeds up. The result is steady, consistent pressure all the time — typically within 2-3 PSI of your target.
What Are the Benefits?
- Consistent pressure — no more drops when multiple fixtures run simultaneously
- Reduced pump wear — smooth speed changes instead of hard on/off cycling extends pump life
- Energy savings — the pump only works as hard as it needs to
- Smaller pressure tank — most constant pressure systems only need a small tank, freeing up space in your utility room
- Built-in motor protection — controllers like the SubDrive Utility include dry-run protection, overload protection, and fault detection
Is It Worth the Cost?
A constant pressure controller adds cost upfront — typically $1,200 to $1,900 depending on the system. But when you factor in reduced pump wear, lower energy bills, and the comfort of consistent pressure, most homeowners find it pays for itself over time, especially if they're already replacing a pump.
It's also worth noting that if you're building a new home or drilling a new well, adding a constant pressure system from the start is much less expensive than retrofitting one later.
Which System Is Right for You?
- Franklin Electric SubDrive Utility UT3P — works with most existing 3-wire submersible pumps up to 2 HP. A great retrofit option if you want constant pressure without replacing your pump.
- Grundfos CU301 + SQE Pump — a fully integrated constant pressure system where the controller and pump communicate directly. The best performance but requires a Grundfos SQE series pump.
Questions? We Can Help.
Not sure whether a constant pressure system makes sense for your setup? Call us at 715-281-5885 and we'll walk you through the options based on your current system and budget.