SC By SCWS Team | January 18, 2026 | 11 min read
Constant Pressure vs Standard Well Pump: Which Is Better?
Tired of pressure drops when someone else turns on water? Constant pressure well systems promise city-like water pressure that never wavers—but they cost more and add complexity. This guide compares constant pressure and standard well pump systems so you can decide if the upgrade makes sense for your household.
⚡ Quick Answer
Constant pressure systems are worth it for homes with high water demands, multiple bathrooms, irrigation needs, or frustration with pressure fluctuations. Standard systems remain a solid choice for smaller households, tighter budgets, or those who prefer simpler technology that's easier to repair.
How Standard Well Pump Systems Work
Traditional well pump systems have worked the same way for decades—and they work well for millions of homes. Here's the basic operation:
The On-Off Cycle
- Pump turns on when pressure drops to the "cut-in" setting (typically 30-40 PSI)
- Pump runs at full speed regardless of how much water you're using
- Pressure tank fills with pressurized water
- Pump turns off when pressure reaches the "cut-out" setting (typically 50-60 PSI)
- Tank supplies water until pressure drops back to cut-in, then cycle repeats
This means your pressure constantly fluctuates within a 20 PSI range. When you turn on a shower, you might start at 55 PSI and gradually drop to 35 PSI before the pump kicks on. Most people don't notice this fluctuation, but some find it annoying—especially during high-demand situations.
Standard System Pressure Cycle
Pump ON → Pressure rises → 50 PSI → 55 PSI → 60 PSI → Pump OFF
Water use → Pressure drops → 45 PSI → 40 PSI → 35 PSI → Pump ON
(Cycle repeats every few minutes during use)
The Pressure Tank's Role
In standard systems, the pressure tank is critical. It must be large enough to:
- Supply water between pump cycles (drawdown capacity)
- Prevent the pump from cycling too frequently (short cycling kills pumps)
- Absorb pressure spikes when the pump turns off
That's why standard systems typically need 50-85 gallon pressure tanks. Learn more about how well pressure tanks work and why size matters.
How Constant Pressure Systems Work
Constant pressure systems take a fundamentally different approach: instead of the pump cycling on and off, it adjusts its speed to match your demand.
Variable Frequency Drive (VFD) Technology
The heart of a constant pressure system is the Variable Frequency Drive (VFD), also called a variable speed drive or constant pressure controller. This electronic device:
- Monitors pressure continuously via a pressure transducer
- Adjusts pump motor speed by changing the frequency of electrical power
- Maintains target pressure (you set it, typically 50-60 PSI)
- Ramps up or down smoothly as demand changes
When you turn on a faucet, the VFD senses the slight pressure drop and speeds up the pump just enough to maintain your target pressure. Turn on three showers? The pump speeds up more. Turn everything off? The pump gradually slows and eventually stops.
Constant Pressure System Operation
Low demand (faucet) → Pump runs at 30% speed → 55 PSI maintained
Medium demand (shower) → Pump runs at 60% speed → 55 PSI maintained
High demand (irrigation) → Pump runs at 100% speed → 55 PSI maintained
(Pressure stays constant regardless of demand)
Why Smaller Tanks Work
Since the pump adjusts speed instead of cycling, you don't need a large tank to prevent short cycling. Constant pressure systems typically use tanks of just 2-20 gallons. The small tank serves to:
- Provide a brief buffer during pump startup
- Absorb minor pressure fluctuations
- Prevent pump from running for tiny water draws
Some homeowners appreciate the space savings from eliminating the large pressure tank.
📊 Side-by-Side Comparison
| Feature | Standard System | Constant Pressure |
|---|---|---|
| Pressure Range | Fluctuates 20 PSI | Stays within 1-2 PSI |
| Pump Operation | On/Off cycling | Variable speed |
| Pressure Tank Size | 50-85 gallons | 2-20 gallons |
| System Cost (Installed) | $1,500-$3,000 | $2,500-$4,500 |
| Energy Usage | Full power when running | Matches demand |
| Motor Wear | Hard start/stop cycles | Soft ramp up/down |
| Complexity | Simple, proven | More electronics |
| Repair Difficulty | Common parts, DIY-able | Specialized service |
Benefits of Constant Pressure Systems
1. Rock-Steady Water Pressure
The headline benefit: your water pressure doesn't fluctuate based on how many fixtures are running. This means:
- No pressure drop when someone flushes a toilet while you're showering
- Consistent irrigation performance across all zones
- Same pressure filling the bathtub as washing hands
- No more scalding when cold water pressure drops
If pressure drops during showers or fluctuating pressure frustrates you, constant pressure solves these problems definitively.
2. Energy Efficiency
Standard pumps run at 100% power even when you only need a trickle of water. Constant pressure pumps only work as hard as needed:
Standard Pump
Running one faucet: Pump runs at 100% power
Running three showers: Pump runs at 100% power
Constant Pressure Pump
Running one faucet: Pump runs at 25-30% power
Running three showers: Pump runs at 70-80% power
Most households see 15-30% energy savings with constant pressure, though results vary based on usage patterns. Heavy irrigation users may see smaller savings since the pump runs at high capacity anyway.
3. Extended Pump Life
Two factors extend motor life in constant pressure systems:
- Soft starts: The motor ramps up gradually instead of slamming to full speed. This reduces electrical and mechanical stress.
- Fewer cycles: Standard pumps might cycle 50+ times daily. Constant pressure pumps run continuously when water is being used but with less wear per hour of operation.
Many constant pressure systems achieve 20-25 year lifespans versus 15-20 years for standard setups—though proper sizing and installation matter enormously.
4. Space Savings
Eliminating the 50-85 gallon pressure tank frees up significant space in your pump house or mechanical room. The small buffer tank takes up minimal room, and the VFD controller is typically wall-mounted.
5. Better for Low-Yield Wells
If your well has marginal production (under 5 GPM), constant pressure can help. By running the pump slower for longer periods, you can draw water at a rate matching your well's yield instead of overwhelming it with high-speed pumping. This reduces the risk of running out of water during peak demand.
Drawbacks of Constant Pressure Systems
1. Higher Upfront Cost
The premium for constant pressure typically runs $1,000-$2,000 over a standard system:
- VFD controller: $800-$1,500
- Pressure transducer: $100-$200
- Compatible pump (if needed): $200-$500 premium
- Additional installation labor: $200-$400
However, savings on the pressure tank (smaller = cheaper) offset some of this.
2. More Complex Electronics
The VFD controller is a sophisticated piece of electronics that can fail. While reliable modern units have failure rates under 3% over 10 years, when they do fail:
- You lose water until it's repaired or replaced
- Replacement controllers cost $800-$1,500
- Not every well service company works on VFDs
- Troubleshooting requires specialized knowledge
⚠️ Power Quality Matters
VFD controllers are sensitive to electrical issues. Power surges, brown-outs, and poor grounding can damage them. If you're in an area with unreliable power, consider a surge protector specifically rated for VFDs, or stick with a standard system.
3. Pump Compatibility Requirements
Not all pumps work with VFD controllers:
- 2-wire submersibles: Not compatible (motor controls built into pump)
- 3-wire submersibles: Generally compatible
- Some jet pumps: May work with the right controller
If you have a 2-wire pump, you'll need to replace it to go constant pressure. See our jet pump vs submersible comparison for more on pump types.
4. Requires Minimum Flow Rate
Most VFD systems need a minimum flow rate (typically 1 GPM) to operate properly. Very small water draws may not engage the system correctly, leading to pressure fluctuations for tiny uses. Some systems handle this better than others.
Cost Comparison Over Time
Let's look at 15-year total cost of ownership:
| Cost Category | Standard System | Constant Pressure |
|---|---|---|
| Initial Installation | $2,000 | $3,500 |
| Electricity (15 years @ avg. use) | $5,400 | $4,050 |
| Pressure Tank Replacement (1x) | $800 | $200 |
| Pump Replacement (if needed) | $2,500 | $0* |
| Controller Replacement (if needed) | $0 | $1,200 |
| 15-Year Total | $10,700 | $8,950 |
*Assumes constant pressure pump lasts full 15 years due to reduced wear
While individual results vary, constant pressure systems often break even or come out ahead over their lifespan when you factor in energy savings and extended equipment life. The break-even point typically occurs around year 8-10.
Who Should Choose Constant Pressure?
✅ Constant Pressure Is Worth It If:
- • You have 3+ bathrooms or high simultaneous water demand
- • Pressure fluctuations during showers annoy you
- • You irrigate with your well and want consistent sprinkler performance
- • Your well has marginal yield (under 5 GPM)
- • You value energy efficiency and lower operating costs
- • Space is limited and you want to eliminate the large pressure tank
- • You plan to stay in the home long enough to see the payback
⚠️ Standard Systems Make More Sense If:
- • You're on a tight budget
- • You have a 2-wire pump you don't want to replace
- • You live in an area with unreliable electrical power
- • You prefer simpler technology you can troubleshoot yourself
- • Your household is small with low water demands
- • You don't notice or care about pressure fluctuations
- • Local well services don't work on VFD systems
Upgrading Your Existing System
Adding a VFD to Your Current Pump
If you have a compatible 3-wire submersible pump, you may be able to add constant pressure without replacing the pump:
- Have a technician verify your pump is 3-wire and in good condition
- Install a VFD controller rated for your pump's horsepower
- Add a pressure transducer to the discharge line
- Replace your large pressure tank with a small buffer tank (optional but recommended)
- Total upgrade cost: $1,200-$2,200 installed
Complete System Replacement
If your pump is aging or incompatible, it often makes sense to replace everything at once:
- New 3-wire submersible pump
- VFD controller
- Small buffer tank
- Updated wiring if needed
- Total package: $3,000-$5,000 installed depending on depth
See our well pump replacement cost guide for detailed pricing on complete system upgrades.
Popular Constant Pressure Brands
Several manufacturers offer quality constant pressure solutions:
Grundfos SQE/CU 301
Premium system with integrated motor/controller. Excellent reliability, higher price point. Best for deep wells and high demands.
Franklin SubDrive
Add-on controller compatible with standard Franklin motors. Good value, widely available service. Popular retrofit option.
Pentair Intellidrive
Compatible with Pentair/Myers pumps. Solid mid-range option with good support network.
Square D Pumptrol CPS
Budget-friendly controller option. Works with various pumps. Good entry point for constant pressure.
Frequently Asked Questions
What is a constant pressure well pump?
A constant pressure well pump uses a variable frequency drive (VFD) to adjust motor speed based on water demand. Instead of cycling on and off like standard pumps, it speeds up or slows down to maintain consistent water pressure—typically within 1-2 PSI of your target setting.
How much does a constant pressure system cost?
A complete constant pressure system typically costs $2,500-$4,500 installed, compared to $1,500-$3,000 for a standard system. The premium is for the variable frequency drive controller ($800-$1,500) and sometimes a compatible pump. Smaller pressure tanks reduce overall costs somewhat.
Will constant pressure save money on my electric bill?
Potentially yes. Constant pressure systems only use the energy needed for current demand—they don't run at full power when you're just washing hands. Energy savings of 15-30% are typical compared to standard systems, though actual savings depend on your usage patterns.
Do constant pressure pumps last longer than standard pumps?
Generally yes. Constant pressure pumps experience softer starts (ramping up gradually instead of slamming to full speed) and fewer on-off cycles. This reduces motor wear. Many constant pressure pumps last 20-25 years versus 15-20 for standard pumps when properly installed.
Can I add constant pressure to my existing well pump?
Sometimes. If your existing pump is compatible (3-wire submersible or certain jet pumps), you can add a VFD controller for $1,000-$2,000 installed. However, 2-wire submersible pumps require replacement. A well technician can assess your current setup.
What's the biggest advantage of constant pressure?
The biggest advantage is consistent water pressure regardless of demand. Whether you're filling a glass or running three showers, sprinklers, and the dishwasher simultaneously, pressure stays the same. No more pressure drops when someone flushes a toilet.
Are there any downsides to constant pressure systems?
The main downsides are higher upfront cost, more complex electronics that could potentially fail, and the need for specialized service. If the VFD controller fails, you lose water until it's repaired. Standard systems are simpler and can often be repaired with common parts.
Do I still need a pressure tank with constant pressure?
Yes, but a much smaller one. Standard systems need large tanks (typically 50-85 gallons) to reduce pump cycling. Constant pressure systems only need a small tank (2-20 gallons) to absorb minor pressure fluctuations and protect the pump during startup.
Ready to Upgrade to Constant Pressure?
We install both standard and constant pressure systems throughout San Diego County. Our technicians can assess your current setup, explain your options, and help you decide whether the upgrade makes sense for your situation—with no pressure to choose the more expensive option.
