--- title: "Stuck Float Valve on a Stock Tank: How to Tell | Trivertix" description: "What a float valve stuck open or stuck shut does to a trough and its storage tank, how fast each goes wrong, worked from sources, and where to set the alerts." url: https://trivertix.com/stuck-float-valve/ updated: 2026-10-19 --- # How to tell a float valve is stuck before the tank overflows or runs dry A float valve stuck open lifts the trough above the line its float shuts off at, until water runs over the rim or out of the overflow, and the pump or the storage tank keeps feeding it day and night. One stuck shut lets the trough fall as the cattle drink and never refill, and the storage tank that feeds it stops falling on a day it should. You can see either by walking out to look, or by watching the level over time: each makes its own shape on a chart of the level, and a high and a low alert line turn those shapes into a message on your phone. By [Luke Patterson](https://trivertix.com/about/), co-founder of Trivertix. Last checked October 19, 2026. ## The shape each one makes Where a storage tank feeds a trough through a float valve, the same fault looks different on the two tanks. A sensor on either one sees it, and a sensor on both sees it soonest. *What the level does over time, on the trough and on the storage tank that feeds it.* | | On the trough | On the storage tank | | --- | --- | --- | | Valve working | A near-flat line at the float, with small dips through the day as the cattle drink and the valve tops it up. | A fall through the day as the herd drinks, faster in the heat, and almost flat through the night. | | Stuck open | A climb from the float line to the rim or the overflow, then a flat line there, above where it has ever sat. | A steady fall at the rate of the supply, the same at 3 a.m. as at noon. | | Stuck shut | A fall in steps as the cattle come to drink, with no recovery after any of them. | A flat line on a day it should have fallen. | ## Stuck open: how fast it pours A valve stuck open passes whatever its supply gives it, and stops only when someone shuts it. Hudson Valve, which makes trough valves, works the sum on its own page: a 2-gallon bucket filled at the supply in 45.6 seconds, and a valve that lets through 80 percent of it. Time a bucket at your own supply to work it for your trough. Source, read October 19, 2026: [Hudson Valve: Flow rate](https://hudsonvalve.com/flow-rate/). - **The open valve:** About 2.11 gallons a minute - **A day stuck open:** About 3,000 gallons, over the rim - **Off a storage tank 8 feet across:** About 1.0 inch every 15 minutes, through the night as well - **The herd, for comparison:** 0.25 to 0.34 inches every 15 minutes, on average over a hot day On the trough, an inch above the float line is about 31 gallons, which this valve pours in about 15 minutes. A high alert line an inch above the float trips at the next reading. On the storage tank the sign is a fall 3 to 4 times the herd's, that goes on after dark, when cattle drink least. On a well, the pump runs with it. On a tank filled by a truck, it is a load poured on the ground. Sources, read October 13, 2026: [University of Nebraska–Lincoln Beef: Water Requirements for Beef Cattle](https://beef.unl.edu/water-requirements-for-beef-cattle/), [NIST Handbook 44 (2026), Appendix C (PDF)](https://www.nist.gov/document/2026-nist-handbook-44-appendix-c). ## Stuck shut: how fast it empties A valve stuck shut wastes nothing, which is why it is easy to miss. The trough holds only so much, and a herd on a hot day drinks it faster than most people guess. The sums below are for 30 cow-calf pairs on a trough 8 feet across, with the float shutting at 20 inches. - **The herd on a hot day:** 750 to 1,020 gallons - **Off this trough:** 23.9 to 32.6 inches a day - **Dry from the float line:** In about 15 to 20 hours - **Left at a low line of 8 inches:** About 6 to 8 hours of water Those are averages over the day. Cattle drink most in the heat of the afternoon, so a valve that sticks in the morning leaves the trough far lower by evening than the average says. On the storage tank the sign is a line that holds flat while the herd is drinking. No alert line catches that, since a full tank crosses neither: it is something you see on the chart, or catch with a sensor on the trough itself. Sources, read October 13, 2026: [University of Nebraska–Lincoln Beef: Water Requirements for Beef Cattle](https://beef.unl.edu/water-requirements-for-beef-cattle/), [NIST Handbook 44 (2026), Appendix C (PDF)](https://www.nist.gov/document/2026-nist-handbook-44-appendix-c). ## Setting the two alert lines The float line is the level the trough holds when all is well. The two alert lines go either side of it, near enough to catch a stuck valve early and far enough not to trip on an ordinary day. ### The high line Between the float line and the rim: here 21 inches, an inch above the float at 20 and three under the rim at 24. Watch a week of readings first, and set it above the highest the trough sits when the valve is working. ### The low line High enough to leave time to drive out: here 8 inches. Work it from your herd at the hottest weather you expect, and the hours it takes you to get there. ### On the storage tank The low line a day of the herd's water above the outlet, as on the guide to cattle water. A valve stuck open reaches it sooner than the herd would, and one stuck shut never does. ### The step it reads The sensor reports a change of a quarter of an inch, about every 15 minutes, so an inch is four steps: enough to tell a valve that has stuck from the ripple of cattle drinking. ## At the trough, once the chart shows it The chart says which way the valve has stuck and when it started. The rest takes a few minutes at the trough. ### Look at the overflow Water running from the overflow or over the rim means the valve is not closing. A trough brim-full with a dry overflow means the float is set too high or the overflow is blocked. ### Lift the float arm If the water stops when you lift it, the valve itself seals, and the float or the arm is the trouble: a float that has taken on water and sinks, or an arm bent or set too high. ### Check the seat If the water runs with the arm lifted, grit, scale or a worn washer is holding the valve open. Shut the supply, open the valve, and clean or replace the seat. ### For one stuck shut Push the float down. If no water comes, look for a kinked or frozen line, a supply that has quit, or a valve clogged with scale or algae. ## Where a level monitor fits A float valve gives no warning, so the usual catch is the next drive past the trough. South Dakota State University Extension cites research that producers may spend over $1,500 a year on fuel checking water. A monitor puts the level in front of you between drives. Source, read October 19, 2026: [South Dakota State University Extension: Water monitoring systems for livestock](https://extension.sdstate.edu/water-monitoring-systems-livestock). Trivertix is one: an ultrasonic sensor at the top of the tank, on a pole over an open trough or in the lid of a closed storage tank, reads down to the water and reports about every 15 minutes by LoRa radio to a receiver in the house, with no cell signal needed at the tank. The receiver shows the level with no subscription. A monthly plan adds the app, with the chart of the level over time and one high and one low alert line, each with its own switch. The first pilot units went onto cattle watering tanks on the Patterson ranch outside Karnes City, Texas, where the tanks sit miles apart. It does not fit every tank: the radio has to reach a receiver in a building with power, a mile or more with a clear line of sight, so a trough far out on a big pasture is a job for a satellite or cellular monitor. And it reads the level, not the valve: it tells you that the water has gone wrong, and the walk to the trough tells you why. [The stock tank monitor, and where it does not fit](https://trivertix.com/stock-tank-monitor/) ## Questions about a stuck float valve ### How do I know if a float valve is stuck open? Water runs from the overflow or over the rim, and the trough sits above the line its float shuts the water off at. On the storage tank that feeds it, the level falls at a steady rate day and night, where it should fall mostly in the heat of the day. A high alert line an inch above the float line catches it within a reading or two. ### How much water does a float valve stuck open waste? All its supply gives it, until someone shuts it. At the flow in Hudson Valve's own worked example, about 2.11 gallons a minute, that is about 3,000 gallons a day. To work it for your trough, time how long a bucket takes to fill at the supply. ### How fast does a stock tank empty when the float valve sticks shut? As fast as the herd drinks. Thirty cow-calf pairs on a hot day take 750 to 1,020 gallons, by the University of Nebraska's figures, or 23.9 to 32.6 inches a day off a trough 8 feet across. A trough that holds 20 inches is dry in about 15 to 20 hours. ### Where should I set the high alert line on a stock tank? Between the level the float shuts the water off at and the rim or the overflow: an inch above the float line is a good start. Watch a week of readings first, and set it above the highest the trough sits while the valve is working, so cattle splashing and a valve that shuts a little late do not trip it. ## Read next ### [How much water cattle drink in a day](https://trivertix.com/cattle-water-use/) Intake by class and temperature, and a herd worked to inches off the tank. ### [The stock tank water level monitor](https://trivertix.com/stock-tank-monitor/) What it does on an open tank, and what it catches. ### [Satellite, cellular or radio](https://trivertix.com/compare/) Five monitors compared, for the trough near the house and the far pasture. ## Be first in line. The waitlist hears the price and the launch date before anyone else. [Join the waitlist](https://trivertix.com/waitlist/)