Filtration & Circulation /
How to Winterize a Pool with a Sand Filter
To close an inground pool with a sand filter, clean the water, turn off the pump safely, drain and protect the filter and lines, then cover the pool for winter.
Archive date: this article was written for PoolSkimmer on Oct 24, 2026 and given the earlier archive date of Aug 25, 2025 so the blog reads as an organized archive. It was not published on that date.
For an inground pool with a sand filter, the closing process should be centred on three objectives: water that is clean, a pump and filter put to rest safely, and plumbing shielded from the cold. The proper way to do it is to clean the pool in the first instance, then winterize the filter and drain points as the manual dictates, and put a secure cover on for the season.
Pre-closing preparation
It makes sense to start with the obvious dirt and debris. A spotless pool will not only be simpler to winterize but you will be less apt to find stains or buildup when summer comes around. Hayward’s own maintenance advice is to skim, brush and vacuum thoroughly so nothing clogs the circulation. This includes tending to the skimmer area.
- Get rid of leaves and anything else floating about.
- Give the walls, steps and corners a good brushing.
- Vacuum up what has settled.
- Make sure the skimmer and pump strainer baskets are empty.
Should the water chemistry require some work, let the test kit and the chemical labels be your guide. There is no place for guessing at amounts or mixing products in a manner not called for by the label.
Shutting down the sand filter
Safety is paramount when dealing with a sand filter. Never put your hands in operating suction equipment. Turn the pump off at the controls and allow the system to come to a complete standstill before you touch a valve or open any housing.
A sensible sequence would be:
1. Cut the power to the pump. 2. See that all circulation has ceased. 3. Debris can now be removed from the baskets. 4. Backwash the filter if your manual indicates you should. 5. Rinse as per the equipment instructions. 6. Put the valve in the position your manual specifies for winterizing.
Do not force a valve; multiport valves, gauges and unions are not all created equal.
Draining the pool and equipment
There is no one-size-fits-all rule for how much to drain; it is a matter of your pool type and the local climate. While many will lower the water to give the skimmers and returns some protection, it is best to consult the pool and equipment manuals.
To guard against freeze damage, you want to ensure water cannot expand in the wrong places. Drain the sand filter tank as directed and pull the plugs where you can. Exposed fittings and plumbing need to be protected and you should use pool antifreeze only if the manufacturer gives the okay and in accordance with the label. Do not improvise with plugs if you are in any doubt as to what they seal, and stay away from live suction work.
Is it necessary to remove the sand?
In most cases, no. Homeowners do not have to dump the sand out of the filter to close the pool. The usual course of action is to leave it in and simply winterize the tank, unless service is advised. If you see a cracked part or a valve that is leaking, however, put the tools down and contact a professional.
When to call in an expert
A qualified pool pro is worth a phone call if you are at a loss with your particular sand filter, or if you are faced with stuck or poorly marked valves. The same goes for electrical issues with the pump or timer, visible cracks from the frost, or if you have a heater or automation system you are not familiar with.
Mistakes to avoid
Some of the more common errors are opening equipment while the pump is still running, leaving behind debris in the baskets or on the floor, or taking chemical shortcuts. Do not try to make electrical repairs yourself or reach into the suction side. A little care in the closing routine will save you trouble in the spring and make for an easier reopening.
Sources and further reading
- [Hayward: Weekly pool maintenance](https://www.hayward.com/maintenance/weekly-pool-maintenance)