A pump that's losing suction tells you in a few predictable ways: the strainer basket won't stay full of water, the returns go weak, the pump gets louder, and the filter gauge sits lower than it normally does. In Houston it tends to happen on a schedule, because Houston drops its leaves twice — once in late fall and again in late winter, when the live oaks shed. Most of the time the fix is an empty basket. This guide is mostly about the times it isn't: a jammed impeller, an air leak, and the seal damage that follows a pump running dry.
Redzone Pools repairs pool pumps across Cypress, Tomball, Katy, Spring and Greater Houston — licensed, insured, usually same day.
National pool advice assumes the leaves come down in October. Houston's don't. Fall color here arrives in late November and runs into December, and a freeze can knock down whatever is left all at once. That fall load comes from trees like Chinese tallow, sycamore, pecan and bald cypress.
Then comes the season national guides miss entirely. Live oaks are semi-evergreen: they hold their leaves through the winter and drop the old ones as the new ones push out in spring. Texas A&M's plant diagnostic lab notes they can look sickly as it warms up in late January and February — right before the drop. The catkins follow: the worm-shaped pollen tassels that collect under oaks after they flower, which Texas A&M AgriLife puts in March and April.
So a Houston pump carries two waves of load: fall leaves from late November through the first freezes, then oak leaves and catkins from late winter into spring. The small stuff is what causes trouble. Big leaves mostly stop at the skimmer basket; twigs, seeds and catkins can make it to the pump basket, and whatever gets past that — or through a cracked basket — ends up in the impeller.
Your filter's pressure gauge splits the problem in half. Learn the reading it settles at when the filter is clean — that's your baseline. A restriction before the pump starves it of water, so pressure drops; a clogged filter after the pump backs the water up, so pressure rises.
| What you see | Gauge vs. your clean reading | Most likely cause | Who fixes it |
|---|---|---|---|
| Air or bubbles in the pump basket; skimmer gulping air | Lower, needle may bounce | Low water level, or an air leak on the suction side | Topping up the water is yours; hunting an air leak is a service call |
| Baskets empty, pump basket full of water, returns still weak | Lower | Clogged impeller | Service call — the pump has to come apart |
| Returns weak, pump sounds normal | Higher | Dirty or failing filter | Clean or backwash it; if it stays high after a backwash, it's filter repair |
| Water dripping from between the pump and the motor | Varies | Failed shaft seal, often after the pump ran dry | Service call, soon |
Your heater and salt system often notice before you do. A Pentair MasterTemp showing ERR PS with the pump running usually means the filter or skimmers need cleaning — see our MasterTemp error code guide. A Hayward H-Series heater shows LO when its water pressure switch opens, covered in our H-Series code guide. And a salt system flags No Flow with the pump still running. All three are reading the same low flow.
One warning before you touch the lid: if the pump has failed to prime, or has been running with no water in the basket, don't open it yet. Pentair's installation guide for its WhisperFlo pump warns that a pump run this way can build up vapor pressure and hold scalding hot water. Turn it off, make sure the valves are open, and wait until the pot is cool to the touch.
If the flow comes back and stays back, that was it. If the basket is clean and the pump still won't pull, keep reading.
The impeller is the spinning part that actually moves the water, and the passages through it are narrow. Debris small enough to get past the baskets — or through a cracked basket, which is why Pentair says to replace one — packs into it until the pump spins and moves very little. Pentair lists a clogged impeller among the causes of reduced flow. Clearing it starts with shutting off the power and taking the pump apart, and if the debris won't come out, Pentair's procedure has the impeller itself removed, cleaned and reinstalled. That's the line where we'd rather you called.
If the water level is right and the baskets are clean but you still see air in the pump basket, air is getting in somewhere before the pump — the lid O-ring, the drain plugs, a fitting or a valve on the suction side. Pentair's troubleshooting starts in exactly those places: the suction piping, the glands on suction valves, the lid and its gasket. What makes these leaks hard to find is that while the pump runs, a suction-side leak pulls air in rather than dripping water out.
This is the one debris season actually causes. A pump that has lost its prime doesn't stop; it keeps spinning with no water in it — overnight, if the timer runs it while nobody's watching. Pentair's manual is blunt about the result: if the pump is run dry, the mechanical seal will be damaged and the pump will start leaking, and the damaged seal must be replaced. It spells out the exact sequence, too: when the water level falls below the suction port, the pump draws air, loses its prime and runs dry. Keep running it that way, Pentair warns, and the damage can reach the pump case and impeller as well.
The tell is water dripping from between the pump and the motor, where the seal sits. Caught early, that's an ordinary pump repair — the kind that often runs $150–$400 with us. Left dripping, water can work its way into the motor, and replacing a single-speed motor is roughly $900–$1,000. The full price list is in our Houston pool repair cost guide.
We start where you did — baskets, water level, lid — and if the flow still isn't there, the pump comes apart: clear the impeller, find the air leak, and check the seal for that tell-tale drip. If the seal is gone, it gets replaced before it takes the motor with it. It's all part of our pool pump repair service, on Pentair, Hayward, Jandy and other major brands.
If your pool sits under a heavy canopy, both seasons hit harder — Memorial and the Villages are the textbook case. If the pump lost its prime after a power outage rather than a leaf drop, the sequence is in our guide to restarting pool equipment after an outage. And for the routine side — how often to empty baskets and clean the filter through a Houston year — see our Houston pool maintenance schedule.
Usually a full skimmer or pump basket, or water that has dropped below the skimmer opening so the pump draws air. If those are fine, Pentair's troubleshooting list points to an air leak on the suction side, a closed suction valve, a clogged or defective strainer gasket, or a clogged impeller. In Houston it clusters in two windows: late November through the first freezes, and late winter into spring, when live oaks drop their old leaves and catkins.
It has lost its prime or something is blocking the flow. Check the water level, the baskets and the lid O-ring, and make sure the suction valves are open. Don't open the pump lid while it's hot: Pentair warns that a pump that has run without water can build up vapor pressure and hold scalding water, so turn it off and let the pot cool first. If it ran dry for long, look for water dripping between the pump and the motor — a damaged seal has to be replaced.
The pump runs, the baskets are empty and the pump basket is full of water, but the returns stay weak and the filter gauge reads lower than its clean-filter number. Pentair lists a clogged impeller as a cause of reduced flow. Clearing it means turning off the power and taking the pump apart, and if the debris won't come out, removing the impeller itself — work for a technician.
Pentair's pump manual lists the causes: an air leak (the suction piping, the valve glands, a lid that isn't secured or a missing lid gasket), not enough water (the suction lines, pump, strainer and volute must be full, the suction valve open, and the water high enough that the skimmer isn't drawing air), a clogged or defective strainer gasket, a clogged impeller, or a clogged strainer. Fill the pump pot with water up to the inlet before restarting, and never run it dry to see if it catches.
In late winter and spring, not fall. Live oaks are semi-evergreen: they keep their leaves through winter and drop the old ones as the new leaves emerge. Texas A&M's plant diagnostic lab notes they can look sickly as it warms up in late January and February, and the catkins — the worm-shaped pollen tassels — follow when oaks flower, which Texas A&M AgriLife puts in March and April. Empty your baskets more often through that stretch.
Tell us what the pump basket looks like, what your filter gauge reads against its clean number, and whether anything is dripping, and we can usually tell you on the phone whether it's a basket, an impeller or a seal — and price it before we come out. Licensed, insured, serving Cypress and Greater Houston.