Pool care is not rocket science — it is a rhythm: a few minutes a week in season, two bigger jobs in spring and autumn, and a handful of checks over winter. This calendar tells you month by month what needs doing right now — and links each step to a detailed guide. Stick to it and you will never have to deal with green water or frozen pipes, only with deciding when to go for a swim.
Overview table: the pool year on a single screen
The table sums up the whole year for an uncovered outdoor pool in Central European conditions. Shift the exact dates according to the weather — it is the water temperature that decides, not the calendar page. With an enclosure or a heat pump the season stretches out; a separate section below covers that.
| Month | Main task (seasonal) | Regularly (weekly/monthly) | Time |
|---|---|---|---|
| January | Check the winter cover after snow and storms | Monthly walk-around: water level and equipment | 15 min/month |
| February | Check the water level and expansion floats | Monthly walk-around, check the equipment pit | 15 min/month |
| March | Order chemicals and spare parts, service the equipment | Schedule the opening date | 1–2 h |
| April | Open the pool, shock treatment, restart the filtration | Daily filtration, clear up the water | 3–5 h + run-in |
| May | Settling in: fine-tune pH, set the filtration run time | Water test 1× a week, vacuum the floor | 30 min/week |
| June | Switch to summer filtration mode (water above 24 °C) | Water test 1–2× a week, clean the skimmer | 30–45 min/week |
| July | Watch for algae in the heat, shock after storms | Water test 2× a week, check the filter | 45 min/week |
| August | Arrange care while you are on holiday | Water test 2× a week, backwash the filter | 45 min/week |
| September | Season wind-down: solar cover, shorter filtration | Water test 1× a week, fish out leaves | 30 min/week |
| October | Winterizing: clean, lower the level, winter chemicals, cover | — | 3–4 h |
| November | Check the cover after the first frosts | Monthly walk-around | 15 min/month |
| December | Season review, plan repairs and upgrades | Monthly walk-around | 30 min |
January and February: the pool sleeps, you just keep watch
A winterized pool needs no work in winter, only supervision. Once a month — and always after heavy snowfall, a thaw or a windstorm — walk around the pool and check three things: the winter cover, the water level and the equipment pit.
Winter cover: heavy wet snow makes the cover sag and can rip out its anchoring. Sweep off any layer above roughly 20 cm with a soft brush or broom, never with a sharp-edged shovel. Check the strap tension and make sure the cover is not resting on the water anywhere — pump off any rainwater that has collected on it.
Water level: it should stay where you set it when winterizing (usually 10 cm below the return jets). A noticeable drop outside evaporation season signals a leak — something far better discovered in winter. The ice sheet will press against the expansion floats, so check they are still in place.
Equipment kept dry: the pit or plant room must stay dry and ventilated. The pump and filter should be drained, dosing tubes removed, electronics disconnected. If water is standing in the pit, pump it out before frost damages the fittings.
March: the month of preparation — order chemicals before the season starts
March is a logistics month. The pool is still asleep, but you are already lining everything up for a smooth opening — whoever leaves the chemicals until May ends up waiting for the courier instead of swimming.
- Chemical stocktake: check last year’s supplies. Liquid chemicals and test tablets often degrade after a freezing winter; powdered pH− and pH+ keep longer. Restock chlorine (shock and slow-dissolving), algaecide, flocculant and fresh test kits.
- Spare parts: inspect the pump lid gasket, O-rings, the filter pressure gauge and the skimmer basket. Order replacements for anything cracked now.
- Equipment service: consider replacing the filter sand (after 3–4 seasons) or the cartridge. Lubricate the valves, check cables and circuit breakers.
- Opening date: plan it for the turn of March and April, as soon as night temperatures stop dropping well below zero.
You can get complete supplies for the whole season in the pool water treatment category — one spring order in a single parcel saves both time and shipping.
April: opening the pool — the earlier, the cheaper
Open as soon as the water stays above 10 °C, ideally while it is still below 15 °C. Algae multiply slowly in cold water, so you can handle the post-winter clean-up with a minimum of chemicals. Every week of delay as the water warms up means more chlorine and more work.
The procedure in brief: remove and clean the cover, top up the water level, restart the filtration, mechanically clean the floor and walls, adjust the pH to 7.0–7.4 and carry out a shock chlorination. Then let the filtration run practically non-stop until the water is clear. You will find the detailed step-by-step procedure in our guide to opening the pool in spring.
May: settling in and getting the filtration right
In May the “opened” pool becomes an “operating” one. The water warms up to 18–22 °C and you fine-tune the two parameters that will decide the whole season.
Chemical balance: in the first weeks after filling or topping up, the pH drifts — fresh water is still settling down. Test once a week and keep the pH between 7.0 and 7.4, free chlorine at 0.3–0.6 mg/l.
Filtration run time: the basic rule says the entire pool volume should pass through the filter 2–3 times a day. In practice: filtration time in hours ≈ water temperature divided by two. At 20 °C that means around 10 hours a day, split into blocks across the daytime, when people swim and the sun is shining. The article on how long to run your pool filter covers the detailed calculation based on volume and pump output.
June to August: peak season and the weekly routine
In summer the pool lives life to the full — and so does everything that should not be living in the water. Warm water above 25 °C, heavy bather load and storms carrying pollen and dust mean the routine speeds up from “once a week” to “twice a week”. The good news: it is still the same five steps.
- Water test 2× a week: pH, free chlorine, and alkalinity once a fortnight. Liquid drop test kits are more accurate than strips; our guide on how to test pool water explains how to measure and how to read the results.
- Empty the skimmer basket and the pump strainer — in summer they fill up with insects and grass within days.
- Vacuum the floor and brush the walls once a week, especially the corners and steps where deposits settle.
- Backwash the sand filter as soon as the pressure gauge rises 0.2–0.3 bar above its clean reading — typically every one to two weeks.
- Shock dose after heavy load: after a storm, heat above 30 °C or a garden party, add shock chlorine in the evening and let the filtration run overnight.
Watch out for algae in the heat: with water above 28 °C a pool can turn green within 48 hours, especially when the chlorine drops and the pH creeps up. The first warning sign is slippery walls — act immediately, not once the water changes colour. You will find the complete rescue procedure in the article on green pool water.
Holidays: a July pool will not survive a week without care unless you prepare it. Before leaving, shock the water, top up slow-dissolving chlorine in a floating dispenser, extend the filtration on the timer and ideally cover the pool. The article on your pool and hot tub while on vacation has a detailed checklist, including the option of asking a neighbour to help.
September: winding down the season — and how to stretch it
In September the water cools below 20 °C and the routine returns to once a week: water test, skimmer, shorter filtration (6–8 hours a day). The main enemy is no longer algae but falling leaves — fish them out before they sink to the bottom and start to decompose.
If you are not ready to stop in mid-September, reach for a solar cover or an enclosure. A solar cover costing around a hundred euros cuts night-time heat loss and adds 2–4 °C; a polycarbonate enclosure extends the swimming season by 4–8 weeks on each end. The article on pool enclosure vs. solar cover compares the options and prices.
October: winterizing — the most important 3 hours of the year
Winterize once the water settles below 12 °C, usually in mid-October. Winterizing earlier, into warm water, risks algae under the cover; leaving it later risks frost in the pipework. The procedure itself: clean the pool and backwash the filter, adjust the pH, dose the winterizing product, lower the water level below the jets, drain the pipework and equipment, put in the expansion floats and stretch the winter cover over the pool.
The most common mistake is skimping on the draining — a burst pipe or pump is the most expensive winter bill you can write yourself. You will find the full procedure with the steps in order in our guide to winterizing the pool step by step.
November and December: checks and a plan for next year
After the first frosts, check that the cover is holding, the floats are doing their job and the pit is dry — from then on, the winter regime of one monthly walk-around applies.
December is ideal for taking stock: what caused trouble this year? A noisy pump, perpetually green corners, dosing chemicals by hand? Winter is the best time to plan upgrades — off season, installation slots are free and there is time to think things through. For inspiration on what pays off first when modernizing an older pool (liner, inverter pump, cover), see the article on renovating an old pool.
How does the calendar change with an enclosure or a heat pump?
An enclosure and heating do not change the individual tasks, but they shift the boundaries of the season — and with them the whole calendar.
- With an enclosure: you open as early as March and close in November. Very little debris falls into the water, so you vacuum less often and chemical consumption drops by roughly a third. Beware of overheating, though: under a closed enclosure the water easily exceeds 30 °C in summer and chlorine breaks down quickly — in hot weather ventilate and test just as diligently as with an open pool.
- With a heat pump: you reach swimming temperatures from April to October. The extended season means the “May” regime starts 4–6 weeks earlier and the “September” one ends a month later — the weekly routine therefore stretches out, but spring opening is easier because the pool spends less time in hibernation.
- Both combined, with year-round operation: winterizing then disappears entirely and is replaced by a winter idle mode: temperature lowered to 10–15 °C, filtration 4–6 hours a day and a weekly water check. Do budget for heating costs, though, which rise sharply in the freezing months.
How to handle the whole calendar in a few minutes a week?
Most of the calendar items can be delegated to technology — and it is precisely automation that turns a pool from a chore into a pleasure.
- A timer or a smart plug (from around €10–20) takes care of the filtration schedule — set it once in May, adjust it in June and September.
- A pool robot handles the weekly vacuuming of the floor and walls; you just knock out its filter.
- Automatic pH and chlorine dosing (or salt water electrolysis) keeps the chemistry in range even while you are away and reduces testing to occasional spot checks.
- Smart water monitors watch the values around the clock and send an alert to your phone before anything goes wrong.
With the full kit, the summer routine drops from 45 minutes to roughly 10 minutes a week. The article on smart pools and automation breaks down what each level of automation costs and where to start.
Frequently asked questions
When exactly should I open the pool and when should I winterize it?
Do not go by the date, go by the water temperature: open when it stays above 10 °C (usually the turn of March and April), winterize when it drops steadily below 12 °C (usually mid-October). Opening into cold water and winterizing into cold water is always the cheaper and safer option.
How often should I test the water in summer?
With water above 24 °C, test pH and free chlorine twice a week, and immediately after a storm or heavy bather load. Outside peak season, once a week is enough. Check alkalinity roughly once a fortnight and chlorine stabilizer once a month.
Do I have to visit the pool at all in winter?
Yes, but only for a check: once a month, and after every snowfall or windstorm, inspect the cover, the water level and that the equipment pit is dry. It takes a quarter of an hour and reveals problems (a leak, a torn cover, water in the pit) before they cause real damage.
What if I skip a month in the calendar?
It depends which one. A missed winter check usually causes no harm, and skipped March ordering only delays the opening. Two points are critical: summer testing (a week without a check in a heatwave tends to end in green water) and October winterizing — undrained pipework can be destroyed by frost, with the bill easily running into thousands of euros.
Is the calendar different for an above-ground pool?
The rhythm is the same; only the wintering differs: smaller above-ground pools are usually drained and packed away for winter, so the winter checks of the cover and floats fall away. A seasonal pool put up only for summer then compresses the whole calendar into May to September — opening doubles as assembly and winterizing as the tidy-up.
Print out the table, hang it in your plant room and the pool year turns into a series of small, predictable tasks. Everything you will need for them — from test kits and chlorine to winterizing products — is gathered in the pool water treatment category, and the other guides in this series are in our Advice Centre.
