Best Automatic Pool Water Levelers and Autofills
An automatic pool water leveler (also called a pool autofill) is a float valve or electronic sensor that tops your pool back up as it loses water to evaporation, so you stop dragging a garden hose out every few days and you never run the pump dry. The right one depends mostly on how permanent you want the install. For most owners, the simplest fix is a hang-in float-valve leveler like the Pool Sentry M-100: it clips to the skimmer or pool wall, you feed it with a garden hose, and a float valve opens and closes just like the fill valve in a toilet tank. If you are building or remodeling and want the hose gone for good, a plumbed deck-mounted leveler (Custom Molded Products or Pentair) hides a canister in the deck and ties into your house water line. For the most precise control plus a safety cutoff, the Jandy Levolor electronic water leveler uses a sensor instead of a float and shuts itself off if it runs too long. And if you just want to try the idea cheaply, a budget adjustable float valve off Amazon works on the same principle for far less money. Whichever you pick, two things matter more than the brand: it must have backflow protection so pool water can never siphon back into your drinking water, and it only adds water, so you still have to test and balance the pool and deal with rain overflow yourself. Here are the picks by situation, and what actually matters.
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Pool Sentry M-100 Automatic Water Leveler
Who it is for: In-ground or above-ground owners who want to stop hand-filling the pool without cutting into the deck or running wiring, and who have a hose bib within reach.
- +The Pool Sentry M-100 is the long-standing no-plumbing pick: a small float-valve box that hangs over the pool wall or sits at the skimmer, fed by a standard garden hose. When evaporation drops the water line, the float drops and the valve opens; when the pool is back to level, the float rises and the valve shuts, exactly like the fill valve in a toilet tank. There is no electricity and no plumbing to install.
- +It mounts in a few minutes, the fill level is adjustable so you can set it to the middle of the skimmer mouth, and it comes with a built-in anti-siphon (vacuum breaker) so pool water cannot be drawn back up the hose into your house supply. That backflow protection is the detail cheap units often skip, and it is the one that matters.
- +Because it runs off a garden hose, it works on any pool that has a hose bib nearby, which makes it the default upgrade for an above-ground pool or an in-ground pool where you do not want to open up a finished deck.
Watch out: It leaves a hose running to the pool and a box hanging at the waterline, so it is not the hidden, permanent look a plumbed unit gives you. A float valve can stick open (overfilling and running up the water bill) or stick closed (no fill), so check it a few times before you trust it unattended, and never leave the hose pressurized for a long trip until you know the valve seals. It compensates for evaporation only; it does nothing about a pool that is too high after rain.
Custom Molded Products or Pentair Deck-Mounted Water Leveler
Who it is for: Owners doing a new build or a deck remodel who want the hose gone for good and a clean, hidden autofill plumbed to the house water line.
- +A plumbed leveler sets a canister into the deck or bond beam with a mechanical float valve inside, tied to a dedicated water line from the house. The only thing you see is a small lid flush with the deck, so there is no hose draped across the patio and nothing hanging at the waterline. The Custom Molded Products (CMP) water leveler and the Pentair automatic water filler are the two you will see most, both using a reliable float valve.
- +This is the set-and-forget option: once it is plumbed and the float is set to the middle of the skimmer, it holds the level for years with no hose to connect. It is the standard way autofills are built into new in-ground pools.
- +Because it is permanent, it is worth doing right: run a dedicated supply line with an approved backflow preventer or air gap, and set the float so the water sits at the right line for your skimmer. Pair it with honest math on what evaporation is costing you in our cost to run a pool guide.
Watch out: This is a real install: plumbing a supply line and cutting a canister into the deck is a pro job on an existing pool, not a drop-in. A mechanical float can still stick open, and because the unit is plumbed and hidden you may not notice it overfilling or masking a leak as fast as you would a visible hose. Confirm your local plumbing and cross-connection code for the required backflow device before you tie into potable water.
Jandy Levolor Electronic Water Leveler
Who it is for: Owners who want the tightest level control, integration with pool automation, and a built-in safety cutoff that a plain float valve cannot give.
- +The Jandy Levolor (Fluidra) swaps the float for an electronic sensor and a solenoid valve. The sensor reads the actual water level and opens the valve only when needed, which holds a tighter, more accurate level than a mechanical float and removes the moving float arm that is the usual failure point.
- +Its real advantage is the run-time safety limit: if the valve stays open longer than it should, the controller shuts it off and flags it, so a stuck valve or a leak does not quietly dump water for days. It can also tie into Jandy automation (AquaLink) so the level shows up alongside the rest of your equipment.
- +Expect roughly $300 to $500 for the unit, more than a float leveler, which buys you the precision and the automatic shutoff. It still needs a plumbed water line with proper backflow protection.
Watch out: It needs both power and plumbing, so it is the most involved install and has electronics that a float valve does not, which is more that can fail. The price only makes sense if you value the precise control and the run-time cutoff; for a basic above-ground pool a float leveler does the same core job for a fraction of the cost. Confirm voltage and valve compatibility if you are wiring it into an existing automation panel.
Adjustable Float-Valve Leveler (ANTEQI, Zuomeng, and similar)
Who it is for: Owners who want to try an autofill cheaply, or who need a simple hose-fed leveler for a seasonal or above-ground pool and do not want to spend much.
- +The budget units (ANTEQI, Zuomeng, Bylot, FixOasis and similar, usually $30 to $60) use the same principle as the Pool Sentry: an adjustable-height float valve fed by a garden hose that opens and closes with the water line. For a fraction of the price they prove out whether an autofill solves your problem.
- +Most have an adjustable arm or body so you can set the fill level, and they hang on the wall or sit at the skimmer with no tools. For a small above-ground pool or a spool that loses a little water a week, one of these is often all you need.
- +Treat the low price as a reason to check the valve before trusting it: fill the pool, watch it shut off cleanly, and confirm it holds. If it seals reliably, you have the same convenience as a name-brand unit.
Watch out: Build quality varies a lot at this price, and a float valve that does not seal cleanly will drip or stick. Make sure the one you buy has an anti-siphon or vacuum breaker; if it does not, add a backflow preventer at the hose bib rather than connect the pool straight to your supply. Check the printed adjustment range so the fill line actually reaches your skimmer, and do not leave a cheap valve pressurized and unattended until it has earned your trust.
What actually matters when buying
Which automatic pool water leveler should you buy?. Start with how permanent you want it. If you want the simplest, cheapest fix and have a hose bib nearby, a hang-in float-valve leveler like the Pool Sentry M-100 clips on, feeds off a garden hose, and needs no plumbing or power. If you are building or remodeling and want the hose gone for good, a plumbed Custom Molded Products or Pentair deck leveler hides a canister in the deck and ties into your water line for a clean, permanent look. If you want the tightest control plus a safety shutoff, the electronic Jandy Levolor uses a sensor instead of a float and cuts off if it runs too long. And if you just want to try the idea cheaply, a budget adjustable float valve works on the same principle for $30 to $60. Across all of them the non-negotiables are the same: backflow protection, a fill level set to the middle of the skimmer, and the understanding that it only adds water.
How does an automatic pool water leveler work?. Two ways. A float-valve leveler works like a toilet tank: a float rides on the water surface, and when evaporation lowers the level the float drops and opens a valve that lets fresh water in; when the pool is back to the set line the float rises and the valve closes. That is the Pool Sentry, the plumbed CMP and Pentair units, and every budget float valve. An electronic leveler (the Jandy Levolor) replaces the float with a sensor and a solenoid valve: the sensor reads the water level and the controller opens the valve only when it needs to, which holds a tighter level and adds a run-time cutoff. Both only ever add water to make up for evaporation. Neither one removes water, so after a heavy rain you still have to drop the level yourself, which our how to lower pool water level guide walks through.
Do you still have to test and balance the water?. Yes, and this is the point owners miss. An autofill adds fresh tap or well water, which dilutes everything already in the pool: chlorine, cyanuric acid, calcium hardness, and especially salt. The leveler keeps the water line right, but it does nothing for the chemistry, so you still test and dose on your normal schedule. Salt pools feel this the most: every few gallons of fresh water lowers the salinity a little, so after a stretch of hot, evaporative weather you often need to add salt back, which you can size with our pool salt calculator. Think of the autofill as handling the water level only, and keep your usual testing and dosing routine on top of it.
Why does an automatic filler need backflow protection?. Because it creates a cross-connection between your pool and your drinking water. If house pressure drops (a water main break, a nearby hydrant opening), water can be siphoned backward, and without protection that means pool water pulled back into your potable supply. That is why plumbing and cross-connection codes require either an air gap or an approved backflow preventer or anti-siphon vacuum breaker on any pool autofill. The Pool Sentry and quality plumbed units build this in; the cheapest hose-fed float valves sometimes do not, so if yours lacks one, add a hose-bib vacuum breaker rather than connect the pool straight to the tap. This is a health-code requirement, not an optional upgrade.
Can an automatic leveler hide a pool leak?. Yes, and that is its one real downside. An autofill keeps the pool full even when water is escaping through a leak, so it quietly tops off the loss and can run your water bill up for months without you noticing a dropping level. A useful rule: a pool normally loses only about a quarter to a half inch a day to evaporation in hot weather, so if your autofill seems to run constantly or your bill jumps, suspect a leak rather than the weather. The electronic Levolor's run-time cutoff is designed to catch exactly this. If you think water is going somewhere it should not, our how to find a pool leak guide covers the bucket test and how to narrow it down.
How we picked
This is a research-based guide. We compared automatic pool water levelers on how they install (hang-in hose-fed float, plumbed deck canister, or electronic sensor), whether they carry proper backflow protection, how precisely they hold the level, how they fail (a stuck float valve versus an electronic run-time cutoff), ease of setting the fill line, and price, across the main names (Pool Sentry, Custom Molded Products, Pentair, and Jandy Levolor) plus budget hose-fed float valves, along with a broad set of owner reviews and installer discussion. We do not bench-test products and we take no payment for placement; a commission never changes a pick. Two cautions outrank any product: an autofill connects your pool to your drinking water, so it must have an air gap or an approved backflow preventer to code, and because it silently replaces lost water it can mask a leak, so watch your water bill and the run time. An automatic leveler is a convenience that keeps the pump from running dry; it does not replace testing, balancing, or dealing with rain overflow.
Keep your water right, too
Gear handles the cleaning; chemistry is the other half. Useful next: how to lower pool water level, how to find a pool leak, cost to run a pool, how to cool down a pool, all buyer guides.
Frequently asked questions
What is the best autofill device for a pool?
For most owners the best autofill is a hang-in float-valve leveler like the Pool Sentry M-100: it needs no plumbing or power, clips to the skimmer or wall, feeds off a garden hose, and has built-in backflow protection. If you are building or remodeling and want a clean, permanent look with no hose, a plumbed Custom Molded Products or Pentair deck leveler hides a canister in the deck and ties into your water line. If you want the tightest control and an automatic shutoff that catches a stuck valve or a leak, the electronic Jandy Levolor uses a sensor instead of a float. Budget adjustable float valves at $30 to $60 do the same basic job if you just want to try the idea cheaply.
How do I control my pool water level?
The ideal water level is about halfway up the skimmer opening, roughly the middle of the waterline tile. Too low and the skimmer sucks air and can run the pump dry, which damages the seal and the motor; too high and the skimmer door cannot skim the surface properly. You can hold that line by hand with a garden hose, but an automatic water leveler does it for you by topping off evaporation automatically. For the opposite problem, lowering the level after heavy rain, you drain off the excess with the filter on waste, a submersible pump, or a siphon, which our guide on how to lower pool water level walks through.
How much does it cost to have someone come fill your pool with water?
A bulk water-delivery service (a tanker truck) typically charges by the load, and a full residential fill of 10,000 to 20,000 gallons usually runs somewhere around $175 to $500 or more depending on your region, water prices, and how many loads it takes. That is for a one-time fill. Filling or topping off from your own garden hose on municipal or well water is far cheaper, often just a few dollars for a top-off, which is exactly what an automatic leveler does day to day. Delivery is mostly worth it when you need a large fill fast or you are on a well that cannot keep up.
What is the cheapest way to fill a swimming pool?
The cheapest way is your own garden hose on municipal or well water; tap water is far cheaper per gallon than a delivery truck. Two things to check first: some utilities add a sewer charge to metered water even though pool water never enters the sewer, so ask whether your utility offers a pool-fill or fill-and-drain credit, and if you are on a well, do not run it dry filling a large pool in one go. For ongoing top-off, an automatic water leveler on your hose or plumbed line is the cheapest hands-off method, since it only replaces the small amount lost to evaporation.
Do automatic pool levelers work?
Yes, reliably, as long as you buy a decent valve and add backflow protection. A quality float-valve leveler holds the water line for years; it fails by sticking, either open (which overfills and runs up the water bill) or closed (which stops filling), so it is worth checking a few times before you trust it unattended. Electronic levelers like the Jandy Levolor add a run-time cutoff that catches a stuck-open valve or a leak automatically. The key limits to keep in mind: a leveler only adds water, so it does not help after rain, and because it silently replaces lost water it can mask a leak, so watch your water bill.