The term “pool drain” is deceptively simple. It actually refers to three completely different systems in your pool, each with its own cleaning and maintenance needs. There’s the deck drain that sits around the pool perimeter catching splashed water, the main drain at the bottom of the pool that’s part of your circulation system, and the suction lines that can become clogged with debris and restrict water flow.
When someone searches for “how to clean a pool drain,” they’re usually dealing with a specific problem: standing water on the deck, reduced suction at the pool floor, or sluggish circulation that’s making water quality difficult to maintain. This guide covers how to clean and maintain all three types of pool drains properly, what causes blockages, and when you need professional help rather than attempting a DIY fix.
Key Takeaways
- Deck drains catch surface water around the pool perimeter and need regular cleaning to prevent standing water and slip hazards.
- Main drains at the pool bottom rarely need direct cleaning but require monitoring for reduced suction and debris buildup on the cover.
- Suction line clogs restrict water flow throughout the system and can be cleared with a drain auger, high-pressure flushing, or plumbing snake.
- Regular maintenance like clearing deck drain grates monthly, monitoring main drain suction, or keeping skimmer baskets clean, prevents most drain problems before they start.
- Portugal’s spring pollen, autumn leaf fall, and pine/eucalyptus debris mean pool drains work harder here than in many other climates and need more frequent attention.
- Natural pools eliminate main drain maintenance entirely and their biological filtration doesn’t rely on floor drains for circulation.
The Three Types of Pool Drains (And What You’re Actually Asking About)
Before getting into cleaning methods, it’s important to clarify which drain you’re dealing with.
Deck Drains (Channel Drains)
These are the linear drains installed around the pool perimeter, usually at the edge of the deck or between the pool coping and the deck surface. They collect splashed water, rainwater, and runoff to prevent standing water on walking surfaces. Deck drains are rectangular channels covered by grates, and they’re the type that most people are referring to when they search for pool drain cleaning.
Main Drains (Bottom Drains)
The main drain sits at the deepest point of the pool floor and is part of your circulation system. It works alongside your skimmers to draw water into the filtration system. Main drains don’t need frequent cleaning themselves. The issue is usually a clog in the suction line leading from the drain, or debris accumulating on the drain cover that reduces flow.
Suction Line Drains
These aren’t technically drains in the visual sense. They’re the pipes that carry water from your skimmers and main drain to the pump. When people say their “drain is clogged,” they often mean a suction line blockage that’s restricting water flow and causing poor circulation.
This guide covers all three, starting with the most commonly needed: deck drain cleaning.
How to Clean a Pool Deck Drain
Deck drains are straightforward to maintain but easy to neglect until standing water becomes a problem. Clean them monthly during the swimming season, and immediately after heavy storms or windy periods when debris accumulation is high.
Step 1: Locate and Remove the Drain Cover
Deck drains are usually installed around the pool perimeter, often running parallel to the pool edge. The drain cover is a long grate that sits flush with the deck surface.
To remove the cover, check first whether it’s held in place by screws or simply friction-fit. Some covers lift out with a flat-head screwdriver gently pried under the edge. Others have small screws at intervals along the channel that need removing first. Work slowly as deck drain covers can be surprisingly heavy, and the grates can bend if twisted.
Step 2: Remove Debris Manually
Put on rubber gloves and reach into the channel. Pull out any visible debris: leaves, twigs, pine needles, insects, small stones, or anything else that’s fallen in. In Portugal, eucalyptus leaves and pine needles are particularly common culprits. Both are small, dense, and pack into drains quickly.
Use a small hand trowel or scoop to reach debris that’s compacted at the bottom of the channel. Don’t just clear the surface layer, dig down to make sure you’re getting everything.
Step 3: Flush the Channel
Once the large debris is removed, use a garden hose with a strong spray nozzle to flush the channel from one end to the other. Start at the highest point and work toward the drain outlet. This clears fine sediment, sand, and smaller particles that you couldn’t remove by hand.
If the water isn’t flowing freely through the channel and out the drain pipe, there’s a blockage deeper in the system. In this case, you’ll need to use a plumbing snake or auger (covered below) or call a professional if the blockage is beyond your reach.
Step 4: Scrub Stubborn Buildup
Over time, algae, mould, and mineral deposits coat the interior walls of the channel. If you notice green slime or white calcium scale, scrub the channel with a stiff brush and a solution of water and white vinegar (50/50 mix). For tougher buildup, a diluted bleach solution works, but rinse thoroughly afterward to prevent bleach from contacting skin or pool water.
Step 5: Check the Drain Outlet
Walk to where the deck drain empties which is usually at the edge of your property or into a storm drain. Make sure water is flowing freely from the outlet and there’s no visible blockage. If water pools at the outlet or drains very slowly, the problem is further down the line and may require professional attention.
Step 6: Reinstall the Drain Cover
Once the channel is clean and flowing properly, replace the drain cover. Make sure it sits flat and flush with the deck surface, a raised or uneven cover is a trip hazard. Tighten any screws securely but don’t overtighten, as this can crack the cover.
How Often Should You Clean Deck Drains?
At minimum, once per month during the swimming season. However, your specific environment may require more frequent cleaning:
- Pools surrounded by trees: Clean every two weeks. Pine, oak, and eucalyptus trees drop debris year-round in Portugal.
- After storms: Always check and clean deck drains after heavy rain or strong winds. Storms deposit large volumes of leaves and dirt in a short time.
- Spring pollen season: April and May in Portugal see heavy pollen loads. Clean weekly during these months if pollen is coating surfaces.
- Autumn leaf fall: October and November require increased frequency as deciduous trees shed.
Prevention is easier than unclogging. A quick five-minute check and clear once a week prevents the need for intensive cleaning later.
How to Clean a Clogged Main Drain (Bottom of Pool)
The main drain itself rarely needs cleaning. It’s designed to be self-maintaining through continuous water flow. Problems arise when the drain cover becomes clogged with debris, or when the suction line leading from the drain develops a blockage.
Clearing Debris from the Main Drain Cover
If you notice reduced suction at the main drain, debris may be covering the drain cover. This is common after storms or periods when the pool hasn’t been brushed regularly.
Use a pool brush or leaf rake to clear any leaves, dirt, or sediment sitting on top of the drain cover. If the cover itself looks coated with algae or calcium deposits, brush it during your regular pool cleaning routine. The circulation system will pull loosened debris into the skimmer and pump basket where it can be removed.
Testing Main Drain Suction
To check if your main drain is drawing water properly, hold your hand over the drain cover while the pump is running. You should feel moderate suction pulling your hand toward the cover. If there’s little or no suction, one of three things is happening:
- The valve controlling flow to the main drain is closed or partially closed. Check your valve settings. Main drain lines usually have a dedicated valve near the pump or filter.
- The suction line is clogged. This requires clearing the blockage (see next section).
- The pump isn’t primed or is losing suction due to an air leak. Inspect the pump basket, lid seal, and all visible plumbing for air intrusion.
How to Unclog a Pool Suction Line
Suction line clogs are more involved than deck drain cleaning and sometimes require specific tools. However, many blockages can be cleared without calling a plumber.
Method 1: Clear the Skimmer and Pump Baskets First
Before assuming a line is clogged, eliminate the obvious culprits. Turn off the pump, remove the skimmer basket and pump basket, and empty them completely. A full basket creates back-pressure that mimics a clogged line. Restart the pump and check if suction improves.
Method 2: Use a Drain Auger (Plumbing Snake)
A hand-held drain auger is the most reliable tool for clearing suction line clogs. These are available at hardware stores for around €30–50 and are straightforward to use.
- Turn off the pump completely.
- Remove the skimmer basket to access the suction line opening at the bottom of the skimmer.
- Feed the auger cable into the line slowly. Lock the cable, turn the drum clockwise, then unlock and feed more cable. Repeat until you meet resistance (either the clog or an elbow in the line).
- Pull the auger back slowly. If you’ve hooked debris, it should come out with the cable.
- Turn the pump back on and check suction.
Be careful with augers in pool lines. The pipes are typically PVC with short-radius elbows that can catch the cable. Don’t force it. If you can’t reach the clog with a 7-meter auger, call a professional with longer equipment.
Method 3: Reverse Flush with a Garden Hose
For clogs closer to the skimmer opening, you can sometimes push the blockage back toward the pump using water pressure.
- Turn off the pump.
- Close the valve to the clogged line so water can’t flow back into the pool.
- Remove the pump basket lid to give the debris an exit path.
- Insert a garden hose into the suction line opening (in the skimmer or at the pump) and pack the gap with a towel to create a seal.
- Turn the hose on full pressure for several seconds.
- Check the pump basket for debris. If the clog is cleared, you’ll see it in the basket.
Important: This method can push debris deeper into the line if it doesn’t work. If you’re not confident, skip this and go straight to the auger or call a professional.
Method 4: Professional Pressure Jetting
For severe clogs deep in the system, particularly calcium deposits, compacted debris, or tree root intrusion (rare but possible in older pools), professional hydro-jetting equipment may be necessary. This uses high-pressure water to blast through blockages that manual methods can’t reach.
If you’ve tried the methods above without success, or if you’re dealing with recurring clogs, call a pool service professional with proper drain-clearing equipment.
Preventing Pool Drain Problems
Most pool drain issues are avoidable with consistent basic maintenance:
Skim the pool daily. The less debris that reaches the pool floor or deck, the less accumulates in drains.
Clean skimmer and pump baskets regularly. These are your first line of defence against clogged suction lines. Empty them every few days during heavy use or leaf-fall periods.
Brush the pool weekly. This loosens debris from the main drain cover and prevents buildup that could restrict flow.
Trim trees and vegetation near the pool. Strategic pruning reduces how much organic material reaches the water in the first place.
Cover the pool when not in use. A pool cover dramatically reduces debris accumulation, particularly during autumn and winter.
Balance water chemistry consistently. Proper pH and calcium hardness levels prevent calcium scale from forming inside pipes, which is one of the causes of suction line restriction over time.
When to Call a Professional
Some drain problems are beyond DIY solutions. Call a pool professional or plumber if:
- You’ve tried clearing a suction line clog with an auger and hose, and suction hasn’t improved.
- Water backs up into your basement or house from a deck drain outlet, this indicates a serious blockage in the main drainage system beyond the pool.
- You notice persistent reduced flow even with clean baskets, clear drains, and proper valve settings.
- Main drain suction has stopped completely and you can’t identify an obvious cause.
- Deck drains repeatedly clog within days of cleaning, this suggests a deeper structural or slope problem that needs professional assessment.
Natural Pools: Eliminating Main Drain Complexity
Conventional pools rely on main drains at the pool floor to create circulation and pull debris toward the filtration system. Natural pools work differently.
In a natural pool, circulation is driven by water movement between the swimming zone and the regeneration zone (the planted biological filter area). There’s no need for a main drain at the pool floor, water flow is managed through surface skimming and the natural convection created by plant uptake and biological activity.
This eliminates one entire category of drain maintenance. There are no suction lines to clog, no main drain covers to monitor, and no concerns about reduced bottom suction affecting water quality. The biological system handles filtration continuously without needing the mechanical floor drain that conventional pools depend on.
For homeowners tired of the recurring equipment issues that come with conventional pool systems, natural pools offer a genuinely simpler alternative, not because they require less attention overall, but because the attention they do need is ecological rather than mechanical.
Oásis Biosistema designs and builds natural pools across Portugal that are suited to the local climate and landscape. If you’re planning a new pool or reconsidering your current setup, our team can explain what’s possible without relying on mechanical drain systems.
Conclusion
Cleaning a pool drain depends entirely on which drain you’re dealing with. Deck drains need monthly manual cleaning to prevent standing water and slip hazards. Main drains at the pool floor need monitoring for reduced suction and occasional brushing to keep the cover clear. Suction line clogs require augers, flushing, or professional help depending on severity.
The common thread is prevention: keep skimmer baskets clean, skim daily, brush weekly, and don’t let debris accumulate. Do those things consistently, and drain problems become rare rather than routine.
FAQ
How to clean a clogged pool drain?
Clear a clogged pool drain using a drain snake or high-pressure water to remove debris. Regularly inspect and flush drains to prevent blockages. If suction remains weak, professional service may be required to resolve deeper obstructions.
What will dissolve hair in a drain?
Hair in drains can be dissolved with enzymatic drain cleaners or a mixture of baking soda and vinegar. These break down organic material safely. Avoid harsh chemicals that may damage pipes. Regular maintenance prevents future clogs.
How to tell if a pool main drain is clogged?
Signs of a clogged main drain include reduced water circulation, weak suction, or debris accumulation. If the pump struggles or water flow is uneven, the drain may be blocked. Cleaning the drain restores proper filtration and pool circulation.
How to clean in ground pool drain?
Clean an in-ground pool drain by removing debris with a drain snake or flushing with water. Regular maintenance prevents blockages. If problems persist, professional inspection may be required to clear deeper obstructions and restore drainage efficiency.
