Vacuuming an above-ground pool with a sand filter means switching your filter to "waste" mode, not "filter" mode, so the debris goes straight out instead of clogging the sand
When you vacuum an above-ground pool, the debris you pull up has to go somewhere. If your sand filter is set to "filter," that debris gets trapped in the sand and clogs it fast. Instead, you switch the multiport valve (the dial on top of your filter) to "waste," which sends everything straight out through a drain line. This keeps your sand clean and your filter working. The trade-off is that you lose some pool water, so you'll need to top it up afterward.
The whole process takes 30 to 60 minutes depending on how much debris is in the pool. You'll need a vacuum head, pole, hose, and a way to prime the hose so water flows through it. If you've never done this before, the priming step is where most people get stuck—it just means filling the hose with water so air doesn't block the suction.
Key Takeaways
- Turn the multiport valve to "waste" before you start vacuuming, or debris will clog your sand filter instead of draining out.
- Prime the vacuum hose by submerging it in the pool and letting water fill it completely before you attach it to the pump.
- Move the vacuum head slowly across the pool floor in overlapping rows, the same way you'd mow a lawn, so you don't miss spots.
- Watch the water level as you work—it drops as water drains to waste, and you'll need to refill the pool when you're done.
- Backwash your filter after vacuuming to clear out any sand that shifted during the process.
Set the multiport valve to waste before connecting the hose
The multiport valve is the dial or lever on top of your sand filter tank. It has several settings: "filter," "backwash," "rinse," "closed," and "waste." You need "waste" for vacuuming. Turn the dial or flip the lever to "waste"—you should feel it click or lock into place. If you're not sure which position is waste, check the label printed on the valve itself or your pool manual.
Once the valve is set to waste, do not turn on the pump yet. You still need to connect the vacuum hose and prime it. Turning on the pump before the hose is attached can damage the pump or create an air lock that stops water from flowing.
Prime the vacuum hose so water fills it completely
Priming means filling the hose with water so there's no air inside. Air blocks suction, so if you skip this step, the vacuum won't work. Lay the hose on the pool deck next to the pool. Take one end and submerge it in the pool water, holding it underwater. Water will start flowing into the hose. Keep the hose submerged and let water fill it completely—you'll see water moving up the hose toward you. This takes 30 seconds to a minute.
Once the hose is full of water, keep that end submerged and quickly attach the other end to the pump intake (the port on the side of the filter tank, usually labeled "intake" or "in"). If water starts leaking out of the connection, tighten the collar by hand. Now attach the vacuum head to the end of the hose that's still in the water. You're ready to turn on the pump.
Vacuum the pool floor in slow, overlapping passes
Turn on the pump. You should hear water moving through the hose and feel suction at the vacuum head. If you don't feel suction, the hose may not be fully primed—turn off the pump, re-prime the hose, and try again.
Once suction is working, move the vacuum head slowly across the pool floor in straight lines, the same pattern you'd use to mow a lawn. Overlap each pass by about 6 inches so you don't leave strips of debris behind. Move at a walking pace—rushing misses debris. Pay extra attention to corners and the deep end, where debris settles. If the vacuum head gets stuck on the pool wall or floor, don't force it; just back up and try a different angle.
As you work, watch the pool water level. It will drop as water drains to waste. Most pools lose about 1 to 2 inches per hour of vacuuming. If the water level drops below the skimmer intake (the opening on the pool wall), turn off the pump and refill the pool with a hose before continuing. Running the pump when the water level is too low can damage it.
Turn off the pump and switch the valve back to filter
When you've finished vacuuming the entire floor, turn off the pump and let it stop completely. This takes 10 to 15 seconds. Then turn the multiport valve back to "filter." This is important—if you leave it on waste, your filter won't work and the pool water will get cloudy.
Disconnect the vacuum hose from the pump intake and the vacuum head. Drain any remaining water from the hose by holding one end up and letting it pour out, or coil it and leave it in the sun to dry. Store the hose, head, and pole in a shaded spot so the sun doesn't crack the plastic.
Backwash the filter to clear sand that shifted during vacuuming
Backwashing reverses water flow through the filter to flush out trapped debris and sand that may have shifted. Turn the multiport valve to "backwash." Turn on the pump and let it run for 2 to 3 minutes. You'll see dirty water flowing out of the waste line. When the water runs clear, turn off the pump.
Switch the valve to "rinse" and run the pump for 30 seconds to a minute. This settles the sand back down. Then turn the valve back to "filter" and turn the pump back on. Your filter is now reset and ready to run normally.
Refill the pool to the correct water level
Because water drained to waste during vacuuming, your pool is now lower than it should be. Use a garden hose to refill it. The water level should be at the middle of the skimmer intake on the pool wall—not so high that water spills over the edge, and not so low that the skimmer can't draw water. Refilling takes 1 to 3 hours depending on how much water you lost and your water pressure.
While the pool refills, you can clean the vacuum equipment. Rinse the vacuum head and pole with fresh water to remove any chlorine residue, which can crack plastic over time. Let everything dry completely before storing it.
Common mistakes to avoid
The most common mistake is forgetting to switch the valve to waste before vacuuming. If you vacuum on the "filter" setting, all that debris goes into the sand and clogs it. You'll then have to backwash multiple times to clear it, wasting water and time. Check the valve position before you start every single time.
The second mistake is not priming the hose. If air is trapped inside, you won't get suction. Some people turn on the pump and wait, thinking suction will build up on its own. It won't. You have to fill the hose with water first. If suction doesn't work after priming, turn off the pump, disconnect the hose, re-prime it, and reconnect it.
A third mistake is vacuuming too fast. Moving the vacuum head quickly across the floor doesn't give the suction time to pull up debris. Slow down to a walking pace and overlap your passes. You'll finish faster overall because you won't have to go over the same spots twice.
Finally, don't ignore the water level. If it drops below the skimmer, the pump can suck in air instead of water, which damages the pump impeller. Check the level every 15 to 20 minutes and refill if needed.
Frequently Asked Questions
What if my pool has a cartridge filter instead of a sand filter?
Cartridge filters don't have a waste setting. Instead, you vacuum on the "filter" setting and accept that the cartridge will get dirty. After vacuuming, you remove the cartridge and rinse it with a hose to clean it. Some people with cartridge filters use a separate drain valve to send debris to waste, but this requires a different setup. Check your filter manual to see what your system supports.
Can I vacuum the pool without switching to waste mode?
You can, but your sand filter will clog much faster. Debris will get trapped in the sand instead of draining out. You'll have to backwash more often, which wastes water. If your filter is already clogged, you may need to backwash several times before it works normally again. Using waste mode is faster and saves water in the long run.
How often should I vacuum the pool?
Vacuum once a week if the pool is used regularly and the area around it is clean. If you have trees nearby, leaves and debris fall in constantly and you may need to vacuum twice a week. If the pool sits unused, vacuum every two weeks to keep the floor clear. Heavy rain or wind can require extra vacuuming.
Why is my vacuum losing suction halfway through?
The hose may have developed a leak or crack. Check the entire length of the hose for holes or splits. If you find one, you can patch it with a vinyl repair kit from a pool supply store, or replace the hose. Another cause is that the pump intake is clogged with debris. Turn off the pump, disconnect the hose, and check the intake port for blockages.
Do I need to add chemicals after vacuuming?
You don't need to add chemicals right away, but you do need to refill the pool with fresh water. Fresh water dilutes the chlorine and other chemicals slightly, so test the water the next day and adjust as needed. If you vacuumed a lot of debris, the pool may look cloudy for a few hours—this is normal and will clear as the filter runs.