Well Water Pressure Fluctuates? Causes & Solutions

Normal vs Problem

Normal Operation

• Pressure varies between cut-in and cut-out
• Example: 40-60 PSI system varies by 20 PSI
• This is how the system is designed
• Pump off at high, on at low

What's NOT Normal

• Rapid cycling (pump on/off every few seconds)
• Pressure dropping dramatically during use
• Pressure surging or pulsing
• Can't maintain minimum pressure

Monitor Your System

• Watch pressure gauge during use
• Note how often pump cycles
• Compare to past behavior

Common Causes

1. Waterlogged Pressure Tank

Most common cause of pressure issues.

• Bladder tank loses air charge
• Tank fills with water instead of holding air
• No cushion = rapid cycling
• Pressure fluctuates wildly

Signs of Waterlogged Tank:

• Tank feels heavy all over (should feel light at top)
• Tap test: sounds solid (should sound hollow at top)
• Pump runs every few seconds

2. Clogged Filter

• Sediment filter restricting flow
• Pressure drops when water is used
• Recovers when not using water
• Easy fix: replace filter

3. Pump Issues

• Pump can't build full pressure
• Worn impellers
• Motor struggling
• May run but underperform

4. Low Well Yield

• Well can't keep up with demand
• Water level drops during use
• Pressure drops when pumping hard
• Recovers when demand stops

5. Pressure Switch Problems

• Contacts sticking or burned
• Incorrect settings
• Causes erratic on/off behavior

6. Leak in System

• Pressure drops when pump is off
• Causes pump to cycle
• Check toilets, pipes, fixtures

7. Multiple Fixtures Running

• More demand than supply
• Normal if pressure drops during peak use
• Not normal if it's dramatic

Diagnosis Steps

Step 1: Check the Pressure Tank

1. Turn off pump power
2. Open a faucet to drain pressure
3. Tap tank from bottom to top
4. Hollow sound = air (good); solid = water (bad)
5. Check air valve (like tire valve) on tank
6. With tank drained, check air pressure (should be 2 PSI below cut-in)

Step 2: Check Filters

• When was filter last changed?
• Is it visibly dirty?
• Bypass filter—does pressure improve?

Step 3: Watch the Gauge

• What pressure does pump cut in?
• What pressure does pump cut out?
• How fast does it cycle?
• Does it reach full cut-out pressure?

Step 4: Check for Leaks

• All fixtures off
• Watch gauge for pressure drop
• If pressure drops, you have a leak

Fixes

Waterlogged Tank

• If just low air: Recharge (drain tank, add air to proper PSI)
• If bladder failed: Replace tank
• Cost: $300-$800 for new tank installed

Clogged Filter

• Replace filter cartridge
• Consider larger filter housing
• More frequent changes if sediment is heavy
• Cost: $10-$50 for filter

Pressure Switch

• Replace switch (inexpensive)
• Or adjust settings
• Cost: $25-$100 for new switch

Pump Issues

• May need pump replacement
• Professional diagnosis recommended
• Cost: $1,500-$5,000+ depending on depth

Low Yield

• Add storage tank to buffer supply
• Reduce demand during peak times
• May need well work (deepening, new well)

Constant Pressure System

For persistent pressure issues, consider:

• Variable frequency drive (VFD) pump
• Maintains constant pressure regardless of demand
• Eliminates normal 40-60 swing
• Cost: $1,500-$4,000 for system

Frequently Asked Questions

Why does my well water pressure go up and down?

Some variation (40-60 PSI) is normal. Excessive fluctuation usually = waterlogged tank, clogged filter, or pump issues.

What causes rapid pressure fluctuation?

Usually waterlogged pressure tank. Tank can't hold air cushion, causing rapid pump cycling. Check tank first.

How do I know if my pressure tank is bad?

Tap test: should sound hollow at top. Check air pressure at valve (with tank drained). If bladder failed, tank fills completely with water.

Why does pressure drop when I use water?

Normal to some extent. If dramatic, check: clogged filter, undersized system, low well yield, or pump struggling.

Can I just add air to my pressure tank?

If bladder is intact, yes. Drain tank, add air to 2 PSI below cut-in. If bladder failed, air will just escape—tank needs replacement.