On this page
Cleaning is not quite the same as full maintenance. A cleaning visit focuses on removing what is floating in the water or stuck to the surfaces and on restoring the filter, while a maintenance plan also takes charge of water balance and equipment checks week after week. The two overlap, so ask exactly what a quote includes. This page covers one-time and recurring cleaning, green pool cleanups, the three common kinds of algae, cloudy water, deep filter cleaning, where drained and backwash water may go, and chemical safety during a heavy cleanup.
One-time pool cleaning vs a recurring pool cleaning service
A one-time job is sized to the problem: a thick layer of leaves after a storm, a pool left untended for weeks, or dull water before a family gathering. A recurring service repeats a shorter routine on a set schedule so the mess never builds up in the first place. Knowing which one you need keeps the quote easy to compare.
- One-time cleanup: debris removal, heavy brushing and vacuuming, a filter clean-out and a water test, often spread over more than one visit when algae is involved.
- Recurring cleaning: skimming, basket emptying, brushing and vacuuming at every visit, with the filter cleaned whenever its pressure calls for it.
- Before a sale or after a move-in: a thorough clean plus a written note on the condition of the liner, fittings and equipment.
- After a storm or flood: silt and debris come out first, and the water is tested before anyone swims, since runoff can carry soil and lawn products into the pool.
- Automatic cleaners help between visits, but they miss steps, corners and the waterline, which still need a brush.
Green pool cleanup: how a cleaner brings a neglected pool back
A pool that has turned green, or dark with rotting leaves, is recovered in stages rather than in a single pass. Pouring chemicals into water still full of debris wastes product, because the sanitizer gets used up on the organic matter instead of the algae.
- Lift out the heavy debris with a leaf net or rake before it reaches the pump and clogs the basket.
- Test the water to see how far sanitizer, pH and alkalinity have drifted, and correct the balance first.
- Brush every surface so the algae is knocked loose into the water, where the treatment can reach it.
- Shock the water at the dose the product label gives for the pool's volume and condition, with the pump running.
- Run the filter around the clock and clean it repeatedly, since it fills quickly with dead algae.
- Vacuum the settled debris, sending it to waste where the filter allows it so it doesn't blow back into the pool.
- Retest before reopening, and keep everyone out until the water is clear and the sanitizer is back where the label allows swimming.
Green, mustard and black pool algae: how each type is cleaned
The colour of the algae tells a cleaner how much scrubbing lies ahead. All three types are handled with the same basic tools, brushing, sanitizer and filtration, but the effort, the brush and the number of visits change from one to the next.
- Green algae floats freely and tints the water, so it usually responds to thorough brushing, a shock treatment and continuous filtration.
- Mustard or yellow algae settles as a dusty film on shaded walls and steps; it brushes off easily and returns unless the brushes, toys and cleaner that touched the water are cleaned too.
- Black algae forms dark spots with a protective outer layer and anchors itself in plaster, grout and rough concrete, so each spot is scrubbed hard and treated more than once.
- Vinyl liners and fibreglass shells need softer brushes than plaster, since a stiff metal-bristle brush can scratch or tear them.
- Algae that keeps coming back points to a dead spot in circulation, a worn or undersized filter, or sanitizer that runs low between visits.
Why pool water turns cloudy and how a cleaning visit clears it
Cloudy water means fine particles are staying suspended instead of being trapped by the filter or broken down by the sanitizer. Good maintenance keeps it from happening; a cleaning visit is usually booked once it has. A careful cleaner works through the likely causes one at a time rather than adding products at random.
- Filter trouble: a dirty, channelled or damaged filter medium, or a pump that doesn't run long enough, lets fine particles keep circulating.
- Low sanitizer: organic matter from swimmers, leaves and pollen builds up faster than the sanitizer can break it down.
- Unbalanced water: a high pH or high calcium hardness can make minerals come out of solution and haze the water.
- Early algae: water often looks dull or milky for a while before it turns visibly green.
- A sudden load: a busy weekend, a storm or pollen season adds more than the system can catch up with.
- Clarifiers and flocculants can help when used exactly as their labels direct, but a floc treatment drops debris to the floor, where it has to be vacuumed to waste.
Deep cleaning sand, cartridge and DE pool filters
Backwashing and hosing off are routine chores; a deep filter clean is what a cleaning service adds when the routine stops working. Over a season, oils, sunscreen, minerals and dead algae bind to the filter medium, so the pressure climbs sooner after each cleaning and the water never quite sparkles.
- Sand filters: a filter cleaner or degreaser dissolves what backwashing leaves behind, and sand that has clumped or channelled is replaced as the manufacturer directs.
- Cartridge filters: the pleats are rinsed, soaked in a cleaning solution and rinsed again, and a cartridge with torn fabric, flattened pleats or cracked end caps is replaced.
- DE filters: the grids come out, are cleaned and checked for tears, and the filter is recharged with the amount of powder its label specifies, handled so the fine dust isn't inhaled.
- Tank and lid: the O-ring is cleaned and inspected, and a cracked tank, broken internal parts or a leaking valve is passed on to a repair technician.
- After any deep clean, the new clean pressure reading becomes the baseline for the next one.
Where backwash and drained pool water can go: Toronto's sewer rules
Cleaning a pool produces wastewater: filter backwash, vacuum water sent to waste, and sometimes a partial drain to lower cloudy or over-treated water. It can't simply be pumped to the street. The City of Toronto's guidance under its Sewers By-law says chlorinated pool water may go to a storm sewer only once it has been dechlorinated to 0.01 mg/L of chlorine or less, with a pH from 6 to 9.5, and never on a rainy day, when it would overwhelm the storm sewer system.
Salt water pools can't drain to a storm sewer at all because of their high chloride levels. Their water goes to the sanitary connection on your own property, onto your lawn if the ground absorbs it, or away with a hauler approved by Ontario's Ministry of the Environment, Conservation and Parks. Filter backwash headed for a storm sewer must be filtered and dechlorinated; otherwise it goes to the sanitary sewer or onto your own property where it can be properly absorbed. Other municipalities set their own rules.
- On the lawn, the water must soak into your own ground without flowing onto neighbouring properties.
- Rain and meltwater pumped off a cover can go to the storm sewer once the leaves and debris are removed.
- Ask the cleaner where the water will go and how it will be tested and dechlorinated before any discharge.
Pool chemical safety during a heavy cleanup
A green pool rescue uses more chemicals, in bigger doses, than a routine visit, which raises the stakes. The Quebec government's guidance on chlorine for pools and spas warns that chlorine in contact with acids can release highly toxic chlorine gas and that combining different products can cause a fire or an explosion. Health Canada adds that household chemicals belong in their original, tightly closed containers, out of reach of children and pets.
- Add each product separately and let it circulate before the next one goes in, as the labels direct.
- Keep swimmers out while the pool is being shocked, until the sanitizer has settled back to the level the label allows.
- Never reuse a bucket or scoop between chlorine and acid, even after rinsing.
- Ask the cleaner to take away empty containers and never leave concentrated products unattended where children can reach them.
Pool Cleaning: frequently asked questions
How long does it take to clean a green pool?
It depends on how far the algae has spread, the size of the pool and how well the filter keeps up. A lightly green pool may clear after one thorough visit, while a pool left for weeks often needs several visits and repeated filter cleaning. Ask the cleaner to explain the plan and how you'll know the water is ready.
What is the difference between pool cleaning and pool maintenance?
Cleaning removes debris and algae and restores the filter. Maintenance adds regular water testing and balancing and a check of the pump, heater and other equipment. Many companies offer both, so read what each visit includes before you compare prices.
Can I drain my pool water into the street?
Not without checking your local rules first. In Toronto, chlorinated water can go to a storm sewer only after it has been dechlorinated to the limits in the city's guidance, salt water pools can't use the storm sewer at all, and no pool water may flow onto a neighbour's property.
Is a robotic pool cleaner enough to keep a pool clean?
It saves a lot of vacuuming, but it doesn't skim, brush the waterline and steps, clean the filter or test the water. Most owners with an automatic cleaner still brush regularly and book a deep clean when the water or filter pressure says it's time.
Does a pool have to be drained to be cleaned?
Rarely. Most cleaning is done with the pool full, and emptying a liner or fibreglass pool can damage it; the pool repair page explains those risks. A partial drain to bring down high readings is a separate decision, made with the local discharge rules in mind.
Sources
Written by the LokalMatch editorial team. Reviewed by Zubair Afzal on September 10, 2026. How we write and check our guides