Best automatic water shut off valves

The Moen Flo 900-001 goes on the main water line where it enters the house and watches every gallon. It reads flow, pressure and temperature, and it can close its own valve when it sees a leak. That’s the job most people mean by an automatic water shut off valve.

Moen’s spec sheet says the ¾ in. model goes on a ¾ in. cold main and can be fitted to a main of 1.25 in. or smaller. It must go after the water meter, the main shutoff and any pressure regulator. Two ¾ in. NPT brass tailpieces come in the box.

It doesn’t need sensors on the floor. Moen says Flo learns the house’s normal water use and flags flow that doesn’t fit, like a toilet that keeps running. It also runs a daily MicroLeak test with the water off, which Moen says finds leaks as small as a drop per minute.

Plan for power and Wi-Fi first. The spec sheet asks for an outlet with continuous power within 6 ft and a 2.4 GHz Wi-Fi network. Moen’s install guide warns that if Flo is plugged in but offline, it drops into local mode and shuts the water off often. Fix weak Wi-Fi at the meter before you install.

Moen’s install guide recommends a continuous pressure of 80 psi or less, and the spec sheet lists 175 psi as the maximum. The device and its power supply must stay between 32 and 140°F. Outdoors, Moen calls for a weatherproof box at least 12 in. above the ground.

The warranty is one year from delivery, and longer coverage comes only through Moen’s FloProtect plan. The app is free, and Moen says no subscription is required. Moen recommends a professional install, since the main has to be drained and cut.

My call: this is the shutoff I’d put on most ¾ in. mains with good Wi-Fi nearby. The bundle listing adds three Moen Flo detectors, model 920-005, for spots like under a sink. Both listings were sold by Amazon.com and in stock on Oct 21, 2026.

The YoLink kit is the no-cut way to automate a main shutoff. The EVO operator bolts onto the ball valve you already have and turns its stem with a motor. Three leak sensors sit on the floor, and when one gets wet, the valve closes.

It works only on the right valve. YoLink recommends ball valves from ½ to 2 in., and its manual says the valve must open and close smoothly with little effort and close fully. The EVO can’t fix a stiff or leaking valve, and a gate valve with a round wheel won’t work.

Install starts by taking off the valve’s handle and nut. A shaft adapter clamps onto the two flats of the valve stem, and a bracket holds the EVO to the pipe; two bracket sizes come in the box. A clutch lets you turn the valve by hand. Press it first, or you can damage the operator.

Detection is by touch, not flow. YoLink’s Water Leak Sensor 1 trips on water deeper than 0.01 in., runs on two AAA batteries and is rated IP68. The listing says the sensors last up to 5 years on batteries. Put them where leaks start: the water heater, the washer and under sinks.

Outages are where this kit shines. YoLink’s Control-D2D pairs a sensor straight to the valve controller, so the shutoff works without internet while both have power and stay in range. The controller takes four AA batteries or a plug-in adapter, and the listing says it can run 2 years on batteries.

Range is the other strength. YoLink’s LoRa radio reaches up to 2,034 ft in open air, per the maker, so a meter in a far corner of the basement or garage is fine. The hub in the kit is needed for app alerts and remote control, and the listing includes 5 free text alerts a month.

My call: if your main has a good quarter-turn ball valve, this is the easiest whole-house shutoff here to install. It won’t catch a slow leak inside a wall the way a flow monitor can. YoLink covers mechanical parts for one year and electrical parts for two. It was sold by Yosmart and in stock on Oct 21, 2026.

Not every house needs a smart main shutoff. If the tank in the garage or closet is the leak you worry about, FloodStop’s kit protects just that heater. A sensor sits in the drain pan or on the floor, and a motorized ball valve on the cold supply closes when the sensor gets wet.

It doesn’t use Wi-Fi or an app. The control panel sounds an alarm, lights up and closes the valve, and the rest of the house keeps its water. FloodStop’s manual says the panel mounts within 30 in. of the valve and has mute, test, open and close buttons.

The valve goes on the cold line between the heater’s shutoff and the heater. This kit, the FS34C, has ¾ in. compression ends. FloodStop’s manual says you may need an adapter and a union or flex connector. The same kit is listed with ½ in. NPT, ¾ in. press and 1¼ in. NPT ends.

Power comes from an AC adapter, with four AA batteries as backup that aren’t in the box. FloodStop says to replace them yearly, and the panel chirps when they run low. Use FloodStop’s adapter extension, up to 30 ft, rather than an extension cord, which the manual says not to use.

The panel cycles the valve once a month, which keeps a valve that rarely moves from sticking. Extra sensors can be wired in series. A paper sleeve on the sensor stops false alarms when it touches a metal pan, and the sensor trips once the sleeve gets wet, per the manual.

The Amazon listing rates the solid brass full-port valve to 140 psi working pressure and lists NSF 61 and AB1953 lead-free compliance and the ICC-ES listing PMG-1511. FloodStop lists a 2 psi pressure drop at 5.5 gallons per minute for ¾ in. and larger valves. Know its limit: water already in the tank can still drain out.

My call: buy this when the water heater is the leak you worry about most, or when you rent and can’t touch the main. The warranty is one year. It was sold by IPS Corp, FloodStop’s maker, and in stock on Oct 21, 2026. FloodStop recommends a licensed plumber if you need extra fittings.

The 900-006 is the same Flo idea built for a 1 in. main. If the pipe coming into your house is 1 in., this is the Flo to buy. Moen’s spec sheet lists it for a 1 in. cold main and allows mains of 1.25 in. or smaller.

A few details differ from the ¾ in. model on Moen’s sheets. The 1 in. sheet allows an outlet within 10 ft instead of 6 ft, and it lists an IPX5 rating against sprayed water. Moen’s drawing lists its main dimensions as 8.58 in., 5.9 in. and 2.6 in.

For a 1¼ in. main, Moen makes the 900-002. Its sheet lists mains of 1.50 in. or smaller and a ⅜ in. hex key in the box instead of the 5/16 in. key. Moen’s install guide says its union nuts are brass, while the ¾ in. and 1 in. models use plastic union nuts.

Everything else follows the same rules. It goes on the cold main after the meter, the main shutoff and any pressure regulator. It needs 2.4 GHz Wi-Fi, an outlet with continuous power, and a spot that stays between 32 and 140°F. Moen’s listing recommends a professional install.

On a well, Moen says to put Flo after the pump, the pressure tank and any filters. If it has to go ahead of a filter, Moen requires a wye strainer with a 100 mesh or finer screen and a blow-down port, so grit from the well doesn’t reach the valve.

One Moen install guide labels the sizes differently, listing the 900-002 as 1.00 in. and the 900-006 as 1.25 in. Moen’s spec sheets and the Amazon listings agree that the 900-006 is 1 in. and the 900-002 is 1¼ in., so this page uses those. Check the box label before you cut the main.

My call: match the Flo to the size of your main. Pick the 900-006 for 1 in. and the 900-002 for 1¼ in. All three listings, including the 1 in. bundle with three detectors, were sold by Amazon.com and in stock on Oct 21, 2026.

The Frizzlife LP365 is a whole-house flow monitor with its own shutoff valve, like the Moen Flo, but it reads flow with an ultrasonic sensor. Frizzlife lists a measuring range of 0.001 to 18 gallons per minute and says it spots changes down to 0.01 gpm.

What sets it apart is the battery. Frizzlife’s manual says that when the LP365 is unplugged, its internal battery keeps it monitoring and able to close the valve on its own. The product page lists 4 to 6 months of standby on a charge. The app needs plug-in power; the shutoff doesn’t.

It fits ¾ in. and 1 in. mains with NPT threads, and two copper adapters come in the box, per Frizzlife. It plugs into a 110 V outlet. The body is 5.5 by 4 by 3 in. and weighs about 3 lb. The listing says it’s certified to NSF/ANSI 61 and 372.

Frizzlife’s manual is strict about install. On a well, it must go after the pump, or the pump can run dry and be damaged when the valve closes. It recommends a bypass pipe so the house keeps water during service, and it calls for a licensed plumber and any local permits.

There are three versions. The LP365 shows flow and pipe temperature. The LP365-P shows flow and water pressure instead, and Frizzlife says every other function is the same. The LPG365 adds three wireless leak sensors on top of the flow monitoring.

Read the warranty terms. Frizzlife gives one year from delivery, and its manual says you must register within 90 days and test the shutoff, battery and alarms once a month. It also caps the maker’s liability at the purchase price and says no product can remove all leak risk.

My call: pick the LP365 when outages are common and you want a flow monitor on the main. Pick the LP365-P to watch pressure instead of temperature. Its manual says to stay under the rated pressure, but I couldn’t find that number published. All three were sold by Frizzlife and in stock on Oct 21, 2026.

Washer hoses fail, and FloodStop’s washing machine kit guards them. Two motorized ball valves thread onto the hot and cold washer valves you already have, and the hoses thread onto them. A sensor on the floor under the washer closes both valves when it gets wet.

There’s no pipe to cut. FloodStop’s manual has you thread the valves onto the washer valves with the outlets pointing down, then snug them a quarter turn with a wrench. The hoses go back on the FloodStop valves. This listing is the straight version, and a 90° version is listed too.

The panel works like the water heater kit: alarm, light, mute, test, open and close buttons, and no Wi-Fi needed. It mounts within 30 in. of the valves, runs on an AC adapter and keeps four AA batteries as backup, which aren’t in the box. If the valves sit far apart, FloodStop sells extension wires.

It cycles both valves once a month. Put the sensor under the washer or in its drain pan. FloodStop’s manual says to leave the paper sleeve on if the sensor will touch the washer or any metal, since bare metal contact would trip it. Extra sensors can be added for a utility sink nearby.

Know what it can’t do. FloodStop’s manual says water already in the washer and hoses can still leak out after the valves close. It also guards only the washer. A burst pipe in a wall or a leak at the water heater is outside its reach, so pair it with spot sensors or a whole-house pick.

The listing rates the brass full-port valves to 140 psi working pressure and lists NSF 61 and AB1953 lead-free compliance and the ICC-ES listing PMG-1511. FloodStop says it installs in about 15 minutes. A pigtail lead in the box connects a FloodStop Wi-Fi unit or a building system, sold separately.

My call: this is the simplest real shutoff for a laundry room, and it suits renters. A braided hose is still worth having, and our washing machine hose guide covers those. The warranty is one year. It was sold by IPS Corp and in stock on Oct 21, 2026.