You’re adding water to your pool every few days. Maybe every day. The autofill runs constantly. Your water bill just doubled. Something is wrong, and you’re pretty sure it’s not just evaporation.
You’re probably right. A pool that loses more than a quarter inch of water per day likely has a plumbing leak. I’ve been tracking down pool leaks across East Honolulu since 2000, and plumbing leaks are still some of the trickiest problems in pool repair. The pipe that’s leaking might be ten feet from where the symptoms show up. The fix might be a $50 fitting or a $2,000 excavation.
Below: how to confirm you have a leak, where plumbing leaks happen, how we find them, why Hawaii plumbing problems are different, and what repairs cost. For a broader view of pool repair topics, see my complete guide to pool repair in Hawaii.
Is It a Leak or Just Evaporation?
Before you call anyone, figure out whether it’s a leak or evaporation. Trade winds, dry days, and constant sun can take a surprising amount of water out of a pool.
Normal evaporation in Hawaii runs about an eighth to a quarter inch per day. During Kona wind conditions with low humidity, it can hit a third of an inch. If you’re losing more than a quarter inch a day, day after day, look into it.
The Bucket Test
This is the simplest, most reliable way to tell evaporation from a leak. Fill a five-gallon bucket with pool water and set it on the top step of your pool so the bucket water level is roughly even with the pool water level. Mark both water levels. Wait 24 hours with the pump running normally. Then compare.
If the pool lost more water than the bucket, you have a leak. The bucket water evaporates at the same rate as the pool water, so any difference is water leaving the system through a leak. If both dropped the same amount, what you’re seeing is evaporation.
Run the test for two to three days to get a reliable reading. One day can be thrown off by a rain shower or an unusual wind pattern.
Pump On vs. Pump Off
Run the bucket test twice, once with the pump running for 24 hours and once with it off for 24 hours. That tells you even more.
If the pool loses more water with the pump on, the leak is on the pressure side of the system (the plumbing between the pump and the return jets). Water pressure is pushing water out through the crack when the pump runs.
If the pool loses more water with the pump off, the leak is likely structural, like a crack in the shell or a separation at the tile line.
If the loss rate is about the same either way, the leak could be on the suction side (between the skimmer and the pump) or in a fitting that’s exposed to water whether the pump runs or not.
Where Pool Plumbing Leaks Happen
Pool plumbing has a lot of joints, fittings, and connections, and any of them can fail. In my experience, leaks show up in the same places again and again.
Suction-Side Leaks
These occur in the pipes that run from the skimmer and main drain to the pump. Suction-side leaks pull air into the system, which is why air bubbles in your pump basket or return jets often signal a suction-side problem. The pipe itself might not be visibly leaking water because the pump is pulling air in rather than pushing water out.
Common spots: the skimmer throat connection (where the pipe meets the bottom of the skimmer), union fittings at the pump, valve connections, and anywhere a pipe transitions from the pool shell into the ground.
Pressure-Side Leaks
These are in the plumbing after the pump. Water is under pressure here, so when a fitting cracks or a pipe separates, water gets pushed out actively. Pressure-side leaks are usually bigger water losers than suction-side because the pump is forcing water through the breach.
Common spots: return jet fittings at the pool wall, the pipe run between the filter and the return lines, heater connections (especially where dissimilar metals meet), and any underground pipe section that’s settled or shifted.
Underground Pipe Leaks
These are the most expensive. Pipes run underground from the pool to the equipment pad, sometimes 20 to 50 feet of buried PVC. When a section of underground pipe cracks or a glue joint fails, the leak is invisible from the surface. You might notice a wet or soft spot in the yard, or you might notice nothing at all except a steadily dropping water level.
Why Hawaii Makes Plumbing Leaks Different
I’ve talked to pool guys on the mainland, and their leak stories don’t sound like ours. Three things make pool plumbing repair harder here.
Volcanic Soil and Rock
Most of East Honolulu sits on volcanic substrate. The soil is a mix of clay, volcanic rock, and coral. This matters for two reasons.
First, the ground shifts. Not dramatically like earthquake country, but slow settling over decades. That settling puts stress on rigid PVC plumbing connections. A pipe that was perfectly aligned when the pool was built 25 years ago may have a joint under tension now. Eventually that tension cracks the fitting.
Second, digging is harder here. Mainland plumbers dig through dirt and clay. We dig through coral rock and volcanic aggregate, which means more labor per foot, longer repairs, and sometimes special tools. A buried pipe repair that might cost $800 on the mainland can run $1,200 to $1,500 here just because of what we’re digging through.
Root Intrusion
Our plants grow hard all year. Roots from monkeypod trees, banyans, palms, and plumeria go looking for water. If you have even a tiny seep in an underground pipe joint, roots will find it. They grow into the joint, widen the crack, and turn a slow leak into a significant one.
I’ve pulled root masses the size of a grapefruit out of 2-inch pool return lines. The pipe had a hairline crack at a 90-degree elbow. A plumeria root found it. Within two years, the root had grown through the fitting and was blocking half the flow.
Homes with mature landscaping near the pool or equipment pad are at the highest risk. If your plumbing run passes under or near a large tree, that’s worth monitoring.
UV Degradation on Exposed PVC
PVC pipe is not designed for prolonged UV exposure. On the mainland, most above-ground PVC gets painted or covered. In Hawaii, I see exposed PVC on equipment pads that’s been baking in direct sun for 15 to 20 years. It turns chalky, becomes brittle, and cracks under stress that healthy PVC would handle without issue.
The fittings on the equipment pad, the unions, the valve connections, and the pipe stubs coming out of the ground all weaken after years in direct sun. A simple bump or a pressure spike that would be nothing for new PVC can crack degraded pipe.
How We Find Pool Plumbing Leaks
Finding a leak takes the right tools and some patience. This is how I work through it.
Visual Inspection
It sounds basic, but looking carefully finds a lot of leaks before any equipment comes out. I check every visible fitting, union, valve, and connection point on the equipment pad. I look for mineral deposits, water staining, wet soil, or active dripping. I check the pump lid and housing. I inspect the filter connections and heater plumbing.
At the pool itself, I check around each return fitting, the skimmer, the main drain area, any lights, and the tile line for cracks or separations.
Pressure Testing
I isolate sections of the plumbing system and pressurize them with air or water, then monitor for pressure drop. If I pressurize the return lines and the pressure holds, the return side is tight. If it drops, I know the leak is somewhere in that section.
That shrinks the search a lot. Instead of 150 feet of plumbing, I might be down to a 30-foot section of return line on the north side of the pool.
Electronic Leak Detection
For leaks we can’t see and can’t pin down with pressure testing alone, we use electronic listening equipment. These devices amplify the sound of water escaping through a crack or fitting. By moving the sensor along the pipe path, we can pinpoint the leak location within a few feet.
This equipment has gotten much better in the last decade. Leaks that used to mean digging test holes can often be found from the surface now, which saves you time and money.
Dye Testing
For suspected leaks at visible fittings or structural cracks, dye testing is straightforward. With the pump off and the water still, I release a small amount of dye near the suspected leak point. If there’s a leak, you can watch the dye get pulled into it. It’s low-tech and works well for confirming a specific spot.
Our pool leak detection service uses whichever of these methods the leak calls for. Most leaks don’t need all of them.
What Pool Plumbing Repairs Cost in Hawaii (2026)
Cost depends mostly on where the leak is and how hard the pipe is to reach. This is what I see across East Honolulu.
| Repair Type | Cost Range | Notes |
|---|---|---|
| Leak detection service | $150 - $400 | Depends on complexity |
| Accessible fitting repair | $150 - $400 | Equipment pad, visible plumbing |
| Underground pipe repair (shallow) | $500 - $1,000 | Under 3 feet, soft soil |
| Underground pipe repair (deep/rock) | $1,000 - $2,500 | Volcanic rock, coral, deep runs |
| Skimmer throat repair | $300 - $800 | Depends on access and pool type |
| Return fitting replacement | $200 - $500 | Per fitting, at pool wall |
| Pipe reroute (above ground) | $400 - $1,200 | When underground repair isn’t practical |
| Full replumb (equipment pad) | $800 - $2,000 | All fittings and pipe on the pad |
One option I recommend when the underground leak is in a section that’s particularly hard to reach: abandon that pipe section and reroute new plumbing on a different path. Sometimes it’s cheaper to run 30 feet of new pipe around an obstacle than to excavate through coral rock to reach a single cracked fitting.
For a broader view of what pool repairs cost across all categories, see my pool repair cost guide.
Prevention: Keeping Your Plumbing Healthy
You can’t prevent every leak. Pipes age, the ground settles, and roots grow. You can lower the odds and catch problems early.
Keep your pool chemistry balanced. Water that’s too acidic attacks copper fittings and can weaken PVC glue joints over time. Water that’s too alkaline builds scale inside pipes, which raises pressure at the fittings. Balanced water protects plumbing from the inside.
Address small leaks immediately. A slow drip at a union fitting costs $50 to fix now. Left alone for a year, that same drip can erode the pipe, damage surrounding fittings, and saturate the soil around your equipment pad. Now you’re looking at $500 or more.
Protect exposed PVC from UV. Paint it or wrap it. A can of PVC-rated paint costs $15 and adds years to exposed pipe life. I’m amazed how many equipment pads I see with completely unprotected PVC that’s been in direct Hawaiian sun for a decade.
Watch your landscaping. If you’re planting near the pool or equipment pad, pick plants with gentler roots. If there’s already a mature tree near the plumbing run, have the lines checked every few years. Catching roots early is far cheaper than replacing a pipe they’ve destroyed.
Watch your water bill. A sudden increase with no change in usage patterns is one of the earliest signs of a plumbing leak. Many of my customers in Kahala and Waialae Iki catch leaks this way before they notice any water level drop.
When to Call for Help
Every pool owner should know the bucket test. Past that, leak detection and plumbing repair are a job for a pro. Pressurizing lines the wrong way can cause new problems, digging in the wrong spot wastes money, and working on pool plumbing without knowing how the whole system is laid out can turn a small repair into a big one.
If the bucket test confirms a leak, call someone with leak detection equipment and experience. In East Honolulu, that’s us. Reach us at 808-399-4388.
For the bigger picture on pool repairs in Hawaii, including pumps, filters, heaters, and everything else on your equipment pad, my complete guide to pool repair covers it all.
