5 Common Pool Filter Problems and How to Fix Each One

Your pool pump runs all day. The timer clicks on and off like clockwork. But the pool water still looks cloudy, or debris keeps floating back into the swimming pool. Sound familiar?

When your filter stops doing its job, the problem usually falls into one of five categories. Some you can fix yourself in an afternoon. Others need professional swimming pool service to get your filter system back on track.

With 15 years in the pool service industry and a decade serving Long Beach independently, we’ve seen every filter issue imaginable. This guide walks you through the five most common issues with pool filters, explains what causes each one, and helps you decide when a DIY approach makes sense versus when to call for help.

We’ll cover clogged media, cracked housings, valve failures, seal problems, and pressure concerns. By the end, you’ll know how to inspect what’s wrong and what to do about it.

What Causes a Swimming Pool Filter to Stop Working?

Pool filters stop working due to five main causes: clogged or damaged filter media, cracked filter housings, faulty multiport valves, worn O-rings and gaskets, or pressure problems from improper sizing or blockages.

Common failure points include:

• Cartridge tears or calcium buildup on pleats
• Sand channeling or hardening in sand filters
• Torn grids in DE filters
• Cracked tanks or manifolds
• Worn seals that let water bypass the filtration

Most problems show warning signs before complete failure. Swimming pool water that stays murky, unusual pressure gauge readings, or visible leaks around the equipment pad typically appear first.

If your pool filter shows any of these symptoms, our Long Beach pool filter repair team can diagnose the issue quickly.

Clogged or Damaged Filter Media

The filter media does the actual cleaning work inside your filtration system. When it fails, water quality drops fast.

Cartridge filters develop problems when the pleats tear, compress from age, or build up calcium deposits that cleaning can’t remove. A cartridge past its prime looks yellow or brown, feels stiff, and may have visible holes or frayed fabric. In our experience, most cartridge filter elements benefit from replacement every one to three years, though actual lifespan depends on pool usage, water chemistry, and how often you clean them.

Sand filters suffer from channeling, where water carves paths through the sand instead of filtering evenly. The sand can also harden into clumps after several years, reducing filter performance. Based on Pool & Hot Tub Alliance guidelines, most sand benefits from replacement every three to five years, though actual lifespan depends on pool usage, water chemistry, and maintenance habits. Regular backwashing helps extend the life of your sand, but eventually the granules wear smooth and stop trapping particles effectively.

DE filters use grids coated with diatomaceous earth powder. The grids can tear, and the manifold holding them can crack. When DE powder keeps returning to your pool, a torn grid is usually the cause. Based on what we see in the field, grids typically last anywhere from two to five years depending on water chemistry, usage patterns, and maintenance.

Warning signs across all types include murky water despite normal pump and filter operation and filter pressure climbing significantly above your normal baseline. As a general guideline, if your gauge reads 8 to 10 PSI higher than your clean filter reading, it’s time to clean or inspect the media.

DIY approach: Regular cleaning and backwashing extends media life. But when cleaning no longer restores clear water, the media needs replacement.

Cracked Filter Tank or Housing

The tank holds everything together under pressure. When it develops a crack, you have a serious problem that affects the entire pool.

Cracks happen from UV degradation over years of sun exposure, impact damage from yard work or falling objects, or simply age. The filter housing on most units is made from plastic or fiberglass, and both materials become brittle over time. While freeze damage is rare in Southern California, it can happen during cold snaps if water sits in the filter tank.

Signs of structural damage include visible cracks anywhere on the tank, water spraying from the housing during operation, or a unit that cannot pressurize to normal operating levels. 

Can you repair a cracked filter housing?

Small crack repairs are sometimes possible using epoxy or fiberglass patch kits. For hairline cracks away from fittings, clean the area thoroughly, apply the epoxy or adhesive according to product directions, and allow full cure time before running the system. Some pool owners have success with plastic welding for certain housing materials.

However, larger cracks or cracks near pipe fittings typically mean the filter housing needs full replacement. The tank operates under pressure when the system runs, so a failed patch can cause flooding or damaged equipment. If the crack returns after an epoxy repair, replacement is your best option.

As Jandy and Pentair certified installers, we can assess whether your housing is repairable or if replacement with a properly sized unit makes more sense for your pool. Based on our experience, well-maintained filter housings can last anywhere from 10 to 20 years depending on material quality, sun exposure, and care. When shopping for replacement equipment, look for filters certified to NSF/ANSI/CAN 50, the national standard covering pool filters, pumps, valves, and other circulation equipment. The CDC’s Model Aquatic Health Code references NSF/ANSI 50 certification for public pool equipment, and while residential pools aren’t bound by MAHC requirements, choosing certified equipment gives you confidence in quality and durability.   

Multiport Valve Failures

Sand and DE filters use a multiport valve to control water flow. This valve lets you switch between filter, backwash, rinse, and waste modes.

The most common valve problem is a worn spider gasket. This star-shaped rubber seal sits inside the valve and directs water to the correct port. When it wears out, water leaks between modes. You might notice water coming from the waste line even when the valve is set to filter mode, or weak water flow returning to the pool.

Other valve issues include a handle that won’t turn or feels loose, a cracked valve body, or a damaged diverter plate inside.

Spider gasket replacement is a reasonable DIY project if you’re comfortable taking the valve apart. Drain the system, remove the valve cover, inspect the old gasket, and install the new one. Lubricate the new gasket with silicone before reassembly. At most pool supply stores, the part generally costs somewhere in the $20 to $40 range, though prices vary by brand and retailer. The job typically takes about an hour for someone comfortable with basic pool equipment, though first-timers may need longer.

Internal damage to the valve body or diverter plate typically requires professional repair or valve replacement.

Because we’re certified for both Jandy and Pentair equipment, we stock common valve components and can often complete these repairs in a single visit. It’s one of those small fixes that prevents bigger problems down the road and keeps your pool running smoothly.

O-Ring and Seal Leaks

Seals keep water where it belongs. When they fail, you get leaks around your pool equipment.

The tank lid O-ring is the most common culprit. It dries out, develops small cracks, and stops sealing properly. Water drips from around the lid during operation. Drain plug seals and pump-to-filter connection points can fail the same way.

Signs of seal problems include water pooling around your equipment, visible dripping during pool pump operation, or air bubbles in the pump strainer basket (which indicates a suction-side leak pulling air into the pipe).

O-ring replacement is straightforward. Remove the old seal, clean the groove, inspect for any damage to the seating surface, and install the new O-ring. Never use petroleum-based products on rubber seals. Most supply stores carry common sizes for popular filter brands.

If you’re seeing leaks at multiple points or cannot identify the source, our team handles pool equipment service throughout Long Beach and can trace the leak quickly.

Pressure Problems: Too High or Too Low

Your pressure gauge tells you a lot about filter health. Learning to read it helps you catch problems early and keep your pool clean.

High pressure (significantly above your clean baseline) usually means the filter is dirty and restricting flow. Backwashing or cleaning the cartridge should bring readings back to normal. If pressure stays high after cleaning, the problem may be a closed return valve, undersized filtration for your pool volume, or a clog in the return pipe. 

Low pressure points to issues on the suction side. Common causes include a clogged skimmer basket, debris in the pool pump impeller, air leaks at the pump lid or fittings, or a motor problem. Low pressure is technically a pump issue rather than a filter issue, but many homeowners notice it at the gauge first.

Normal operating pressure varies by equipment. According to Pentair’s equipment guidelines, most residential filters run somewhere in the range of 10 to 25 PSI depending on filter size, pump horsepower, and plumbing configuration. The specific number matters less than knowing your baseline. Write down the pressure reading after you clean your filter so you have a personal reference point for your system. When pressure climbs 8 to 10 PSI above that baseline, it’s generally time to clean or inspect.

In coastal Long Beach neighborhoods like Naples, Belmont Shore, and Peninsula, heavy accumulation from trees and marine air can affect filter pressure more frequently. Inspect your skimmer and pump baskets weekly during peak seasons to maintain proper water flow.

When to Repair vs. Replace Your Pool Filter

Not every problem needs a full replacement. Here’s how to decide whether repair makes sense for your swimming pool.

Estimated lifespans by type (based on our field experience):

• Cartridge filter: Media typically lasts 1 to 3 years; housing can last 10 to 15 years or longer with proper care
• Sand filter: Sand generally lasts 3 to 5 years per PHTA guidelines; tank can last 15 to 20 years under normal conditions
• DE filter: Grids often last 2 to 5 years depending on water chemistry; tank can last 10 to 15 years with proper maintenance

These are estimates based on what we commonly see. Your actual results depend on water chemistry, usage, sun exposure, and how well the equipment is maintained.

What repairs typically cost in our area:

Based on our service work in Long Beach, most filter repairs run somewhere between $150 and $400 depending on the component, parts needed, and labor involved. Simple fixes like O-rings or gaskets fall on the lower end, while valve replacements or media changes cost more. Every situation is different, so we provide specific quotes after assessing your system.

What replacement typically costs:

From our installation experience, filter replacement generally ranges from $400 to $1,500 or more depending on filter type, size, brand, and installation complexity. Larger pools, difficult access, or upgrades to higher-capacity equipment push costs toward the upper end.

Repair often makes sense when:

• Only one component has failed
• The unit is under 10 years old
• No tank cracks or structural damage exists

Replacement often makes sense when:

• Multiple components are failing
• The housing shows cracks or deterioration
• The unit is undersized for your pool
• You want to upgrade to a more efficient system

Professional advice matters here. If a modest repair will give you several more years of reliable service, that’s what we recommend. Our approach has always been to educate homeowners so they can make informed decisions about pool installation and equipment choices.

Understanding your filter system puts you in control. You’ll know what questions to ask, when DIY makes sense, and when professional help is the smart choice.

Questions about whether your filter needs service or replacement? Seek professional swimming pool help from our Long Beach team. We can inspect your system and give you a straightforward answer about the best path to clean and clear pool water. We’ll be here when you need us, not just for this repair but for ongoing questions. Call Adam’s Pool and Spa at (562) 522-2203.

Note: Lifespan estimates, repair costs, and replacement costs are based on Adam’s Pool and Spa’s service experience in the Long Beach area. Actual results vary by equipment brand, installation conditions, water chemistry, maintenance practices, and local labor rates.

FAQs

What are the signs that my pool filter needs repair?

Your filter usually tells you something is wrong before it stops working completely. Here’s what to watch for:

Pressure gauge problems

• Reading climbs 8-10 PSI above your normal baseline
• Pressure stays high even after cleaning
• Gauge drops to zero (possible leak or pump issue)

Water quality changes

• Pool water stays cloudy despite good chemistry
• You see debris floating back into the pool
• Water flow from return jets feels weak

Visible damage

• Cracks anywhere on the filter housing
• Water leaking around the tank or fittings
• Unusual sounds during pump operation

From our experience: In coastal Long Beach neighborhoods like Belmont Shore and Naples, salt air speeds up wear on plastic housings. We often see cracks on filters that look fine otherwise. A quick visual check during your weekly maintenance can catch problems early.

When to act fast:

How do I fix high filter pressure?

High pressure usually means something is blocking water flow through the filter. The good news? This is often a simple fix.

Step-by-step for cartridge filters:

1. Turn off the pool pump
2. Open the air bleeder valve on top of the filter
3. Remove the tank lid (may need to release clamp band)
4. Lift out the cartridge
5. Rinse between all pleats with a garden hose
6. Check for tears or damage while cleaning
7. Reinstall cartridge and lid
8. Turn pump back on and bleed air until water sprays steadily

For sand filters:

1. Turn off pump
2. Move multiport valve to “Backwash” position
3. Turn pump on for 2-3 minutes until sight glass runs clear
4. Turn off pump
5. Move valve to “Rinse” for 30 seconds
6. Return to “Filter” position

Pro tip from our team: If pressure stays high after a good cleaning, the problem may not be the filter at all. We’ve seen plenty of cases where a partially closed return valve or a clogged impeller caused high readings. Check the simple stuff before assuming you need new filter media.

Normal pressure ranges vary by system. Write down your pressure right after cleaning. That’s your baseline. Most residential setups run somewhere between 10 and 25 PSI, depending on equipment.

What should I do if my filter housing has cracks?

Cracks are serious. A cracked housing can’t hold pressure properly, which means poor filtration and potential flooding.

If you spot a crack:

1. Turn off the pump right away
2. Note the crack location and size
3. Take a photo for reference
4. Decide: temporary patch or replacement?

Small hairline cracks (away from fittings):

You can try a temporary repair with pool-rated epoxy or fiberglass patch material. Clean the area well, apply the adhesive, and let it cure fully before running the system. But be honest with yourself—this buys time, not years.

Larger cracks or cracks near fittings:

These need housing replacement. Patches won’t hold under pressure at connection points.

What we tell Long Beach homeowners: If your filter is over 10 years old and showing cracks, replacement usually makes more sense than patching. As Jandy and Pentair certified installers, we can match you with the right size unit and make sure it’s set up correctly. A proper installation lasts much longer than a series of patch jobs.

Crack location matters:

Why isn’t my cartridge filter cleaning my pool water?

Cloudy water with a running filter frustrates everyone. Let’s work through the common causes.

Check these first:

• Cartridge condition — Look for tears, crushed pleats, or brown discoloration that won’t rinse off. Worn cartridges can’t trap fine particles.
• Run time — Most pools need 8-12 hours of filtration daily. Cutting run time to save on electricity often backfires.
• Chemistry — High calcium, phosphates, or metals can look like filter problems. Test your water before blaming the filter.
• Installation — After cleaning, make sure the cartridge seats properly with no gaps. Air leaks around the lid let dirty water bypass the media.

Cartridge lifespan factors:

From our field experience: Here in Long Beach, pools near the beach in areas like Peninsula and Alamitos Bay deal with more airborne grit and salt residue than inland pools in Bixby Knolls or Los Altos. That fine stuff clogs cartridge pleats faster. We often recommend more frequent cleaning or a larger filter for coastal properties.

When it’s time for a new cartridge:

• Pleats stay flat or crushed after cleaning
• Material feels stiff and brittle
• Pressure jumps back up right after cleaning
• Visible holes or tears in the fabric

In our experience, most cartridges last one to three years depending on conditions and care.

How do I fix a pool filter that’s leaking water?

Leaks waste water and reduce filter performance. Finding the source is the first step.

Common leak locations:

• Tank lid O-ring — Most common. Dries out and cracks over time.
• Drain plug — Check for loose plug or worn gasket.
• Pressure gauge fitting — Small drips here are easy to miss.
• Pump-to-filter union — Connection point between equipment.
• Tank body cracks — See crack section above.

How to fix an O-ring leak:

1. Turn off pump and release pressure
2. Remove the tank lid
3. Pull out the old O-ring (it may be stuck in the groove)
4. Clean the groove with a rag—remove all old lubricant and debris
5. Inspect the groove for cracks or damage
6. Apply silicone lubricant to the new O-ring (never petroleum products)
7. Seat the O-ring evenly in the groove
8. Replace lid and tighten clamp
9. Turn on pump and check for leaks

Advice from our technicians: We keep common O-ring sizes on our trucks because this repair comes up so often. If you’re buying your own, take the old O-ring to the pool store for an exact match. Wrong size means more leaks.

Leak troubleshooting guide:

Why does my pool filter constantly need cleaning?

If you’re cleaning your filter every week or two instead of every month, something else is going on.

Common causes of rapid filter clogging:

• Undersized filter — Filter too small for pool volume or pump flow rate
• Oversized pump — Pushes more water than filter can handle
• Heavy debris load — Trees, landscaping, or coastal grit overwhelming the filter
• Algae bloom — Even treated algae leaves behind fine particles
• Construction dust — Nearby projects send fine particles into the pool
• Poor water chemistry — Oils, lotite, and minerals coat the filter media
• Skimmer neglect — Full baskets let debris reach the filter

What we see in Long Beach: Properties with mature trees in neighborhoods like Bixby Knolls and El Dorado Park Estates often deal with leaf debris and pollen that overwhelm smaller filters. Sometimes the solution isn’t more cleaning—it’s a filter upgrade or adding a leaf canister to catch debris before it reaches the filter.

Questions to ask yourself:

• How old is my filter? (Older, smaller filters may not match modern pumps)
• When did I last upgrade any pool equipment?
• Has landscaping changed since the pool was built?
• Am I running the pump long enough each day?

Our honest take: If you’re spending your weekends cleaning filters instead of enjoying your pool, it’s worth having a professional evaluate your system. Sometimes a modest equipment upgrade solves years of frustration.

How often should I replace my pool filter cartridge versus just cleaning it?

Cleaning extends cartridge life, but every cartridge eventually wears out.

Cleaning schedule:

• Routine rinse: Every 4-6 weeks during swim season
• Deep clean: 2-3 times per year (soak in filter cleaner solution overnight)
• Pressure trigger: Whenever gauge reads 8-10 PSI above clean baseline

Signs your cartridge needs replacement (not just cleaning):

• Won’t come clean no matter how long you rinse
• Pleats stay crushed or flattened
• Material feels hard and brittle instead of flexible
• Visible tears, holes, or fraying
• Pressure spikes back up immediately after cleaning
• Cartridge is more than 2-3 years old

Cartridge lifespan estimates:

Our recommendation: Don’t push a cartridge past its useful life to save money. A worn cartridge makes your pump work harder, can’t trap fine particles, and often costs you more in chemicals trying to keep cloudy water clear. Fresh media pays for itself in water quality and equipment life.

Can I do pool filter repairs myself or should I hire a professional?

Some repairs are easy DIY projects. Others really need professional help.

Good DIY projects:

• Cartridge cleaning and replacement
• O-ring and gasket replacement
• Basic pressure troubleshooting
• Backwashing sand filters
• Spider gasket replacement (if you’re handy)

Better left to professionals:

• Cracked housing assessment and replacement
• Multiport valve internal repairs
• Plumbing modifications
• Electrical issues with pump
• Problems you can’t diagnose after basic checks
• Filter sizing and system balancing