Leaving a pool robot in the pool over winter

Makers say no, not for the whole season. The robot comes out.

Nobody swims while the robot is in the water. Aiper says you should never swim while a robotic cleaner is in the pool.¹ A corded model's cable is an entanglement risk, and even a cordless robot is a heavy underwater obstacle that can cause injury.¹ Dreame also says no automatic cleaner should be in the pool with swimmers, because of entanglement hazards.² Run the robot or leave it in only when the pool isn't being used, and take it out before anyone swims.

Aiper says makers advise against leaving a robotic cleaner in the pool for good.¹ The same page says an overnight or weekend stay is fine.¹

So a night in the water is one thing. A winter is another.

Why makers say take it out

Chemicals. Maytronics says chlorine and similar chemicals can wear out a robot's plastic parts.³ Aiper adds that continuous exposure to pool chemicals and water pressure "can degrade the unit faster than expected".¹

Sun. Maytronics warns that intense exposure to the sun can damage some of a robot's plastic parts and seals.³ Dreame says "UV rays break down the plastic housing of the cleaner".² A robot floating or sitting at the waterline gets that sun.

Design. Dreame sums it up: pool robots are "made to run in water, not to stay there".²

Cold. Another maker's guide says that once the water falls under roughly 10°C (50°F), most makers want the cleaner out for the season.⁴

What if the pool stays open?

Say you live somewhere mild and keep the pool running. The advice doesn't really change. The robot still sits in water and chemicals. Once the water gets as cold as the guide above describes, most makers say to take it out.

Your manual is the deciding document. Look for its lowest water temperature and any note about leaving the unit in the pool. If you can't find one, ask the maker.

What about a winter cover?

Aiper says robotic cleaners "can operate under most pool covers".¹ That's about running them, not about leaving them there for months.

With a corded robot under a cover, the same page says to make sure the cable does not interfere with the cover.¹ Check your manual first.

The better plan

For a clean start in spring, do this:

• Run the robot a few times before you close up, then pick your stopping day.
• Take it out, rinse it and dry it. See cleaning and rinsing.
• Store it indoors, somewhere dry and frost-free.

For the full reasoning, see why store a pool robot for winter.

Short stays are a different matter

The advice above is about months, not hours. Say a late cycle ends after dark. Aiper says it is generally fine to leave the robot in overnight. Take it out the next morning to rinse it and clear the filter.¹

Winter isn't a late cycle, though. A robot that has sat in cold, chemical-treated water for weeks is a different case from one that sat overnight.

Before you close the pool

Dreame says to take the cleaner out before shocking the pool and before backwashing the filter.² For any other pool chemical, follow the product label and your robot's manual.