Tank Level Monitoring: 7 Proven Ways to Stop Costly Spills

Last updated: 13 July 2026

TL;DR: Tank level monitoring replaces manual dipsticks with battery-powered sensors that report fuel, water, chemical and waste tank levels every 10 to 60 minutes over LoRaWAN. You get run-dry and overflow alerts before they happen, sudden-drop alarms that flag fuel theft, and a level history that supports UK oil storage compliance. Sensors such as the Milesight EM500-UDL run for around 10 years on one battery, with no SIM cards and no wiring.

What is tank level monitoring and how does it work?

Tank level monitoring is the continuous, remote measurement of liquid or solid level inside a storage tank using a sensor that transmits readings over a wireless network to a dashboard. Instead of someone driving to site with a dipstick, the tank reports its own contents, and thresholds trigger alerts for low level, overflow risk or abnormal loss.

A tank level monitoring system has four parts. A level sensor (ultrasonic, hydrostatic pressure or radar) takes a reading on a schedule you set. A low-power radio, typically LoRaWAN, sends that reading to a gateway up to several kilometres away. The gateway forwards it to a network server and dashboard. Rules on the platform then compare each reading against your thresholds and fire email, SMS or webhook alerts.

The same architecture covers every tank type on a UK site: diesel and heating oil, potable and process water, AdBlue, chemicals and dosing fluids, waste oil, slurry and effluent. What changes is the sensor you screw into the top (or drop to the bottom) of the tank, not the network or the platform. That is why remote tank level monitoring scales so cheaply once the first gateway is on the wall.

What does manual tank dipping actually cost UK sites?

Manual dipping costs you labour, accuracy and reaction time. A dip is a single stale reading that is wrong the moment a pump starts, so sites run out, overfill, or discover theft weeks late. Tank level monitoring removes the site visit entirely and turns every tank into a live data point with an audit trail.

Consider what a dipstick round actually involves: someone climbs a ladder, opens an access hatch in the rain, reads a wet stick or a float gauge, and writes the number in a book. On a fuel distributor’s estate or a farm with a dozen tanks, that is hours of driving each week for data that is out of date by lunchtime.

The failure modes are expensive. Oil has consistently been among the UK’s top three pollutants over the past five years, according to the Oil Care Campaign run by the UK environmental regulators. In one year alone, over 3,300 oil pollution incidents were reported to the UK environment agencies, nearly 10 every day, and tank overfills and unnoticed leaks are classic causes.

Theft is the other silent loss. NFU Mutual reported that fuel theft doubled in 2022 as diesel and heating oil prices spiked, and its Rural Crime Report 2025 still puts the cost of UK rural crime at an estimated 44.1 million pounds for 2024. If nobody reads the tank between deliveries, a few hundred litres siphoned overnight simply never shows up without tank level monitoring in place.

Ultrasonic vs pressure vs radar: which tank level sensor is best?

Ultrasonic sensors are the default for tank level monitoring on most fuel, water, chemical and waste tanks up to 10 m deep: non-contact, self-cleaning and inexpensive. Submersible pressure sensors win for deep water, boreholes and foamy liquids. Radar wins where heavy vapour, extreme temperature swings or pressurised vessels defeat sound-based measurement, at a much higher price.

An ultrasonic sensor mounts on top of the tank and fires sound pulses at the liquid surface, timing the echo. Because nothing touches the liquid, there is no fouling or corrosion, and the same unit works over diesel, water or effluent. The trade-offs: a short blind zone below the transducer, and heavy foam or dense vapour can absorb the echo.

A hydrostatic pressure sensor, such as the submersible Milesight EM500-SWL, sits at the bottom of the tank and calculates depth from the weight of liquid above it. Foam and vapour are irrelevant, and ranges reach far beyond 10 m, which suits reservoirs, wells and river gauging. It does touch the liquid, so aggressive chemicals need compatible wetted materials.

Radar (and guided-wave radar) measures with microwaves instead of sound, so it shrugs off vapour, vacuum and temperature gradients. For a heated bitumen tank or a solvent vessel it is the right answer. For a farm diesel tank it is over-specified: you pay several times the cost of ultrasonic for accuracy you will not use.

How do LoRaWAN ultrasonic sensors kill manual dipping?

A LoRaWAN ultrasonic sensor such as the Milesight EM500-UDL reads the tank every few minutes, runs about 10 years on one 19,000 mAh battery, and reaches a gateway up to 10 km away in line of sight. Fit it, set thresholds, and tank level monitoring runs itself: the dipstick round, the run-dry incidents and the surprise empty tank all disappear.

The EM500-UDL ultrasonic level sensor is the workhorse of LoRaWAN tank level monitoring. Its datasheet covers ranges from 0.25 m up to 10 m depending on variant, with accuracy of plus or minus 1% of full scale and 1 mm resolution, in an IP67 enclosure rated for minus 30 to plus 65 degrees Celsius. Milesight’s own engineering notes on ultrasonic tank accuracy explain how echo processing keeps that 1% figure honest in real tanks.

Battery life is the spec that makes the economics work: 10 years at a 10-minute reporting interval at 25 degrees Celsius, on a replaceable Li-SOCl2 cell. There are no SIM contracts and no mains power runs to dig. The sensor also stores 1,000 readings locally and retransmits them if the network drops, so your level history has no holes.

Two siblings round out the family. The EM400-UDL adds a three-axis accelerometer and tilt detection for waste containers and mobile tanks, and the EM400-TLD swaps ultrasound for a time-of-flight laser where a narrow beam suits baffled or slim tanks. All of them speak standard LoRaWAN, so one gateway serves the whole estate, whether that is a depot, a farm or a water treatment works.

What alert thresholds and telemetry cadence should you set?

Set four alert thresholds in your tank level monitoring platform: high-high at 90% for overflow, high at 80% to pause filling, low at 25 to 30% to trigger reordering, and low-low at 10 to 15% for run-dry protection. Report every 10 to 15 minutes for active tanks, hourly for slow ones, and enable sudden-drop alarms for theft and leaks.

The overflow pair matters most during deliveries. A high alarm at 80% tells the operator to slow down; high-high at 90% is the hard stop that keeps the fill inside the tank rather than inside the bund. Because the sensor reports during the fill, the alert arrives while the tanker is still on site, not in tomorrow’s log review.

The low pair converts tank level monitoring into automatic stock control. The 30% threshold gives your fuel supplier a comfortable lead time to schedule an economical delivery route; the low-low alarm is the safety net that stops a generator, boiler or dosing pump running dry. Fuel distributors flip the same logic around to plan top-ups across hundreds of customer tanks.

Cadence is a battery trade-off, not a technical limit. The EM500-UDL’s 10-year rating assumes 10-minute reporting, which suits generator day tanks and busy depots. A heating oil tank that moves 2% a day can report hourly and still catch every event, stretching battery life further. Critically, threshold and change alarms transmit immediately regardless of cadence, so a sudden 5% drop at 2 am, the classic fuel theft signature, raises an alert within minutes.

Do UK oil storage regulations require tank level monitoring?

No regulation mandates telemetry, but the Control of Pollution (Oil Storage) (England) Regulations 2001 make you responsible for storing oil so it cannot escape. They apply to most containers over 200 litres and demand 110% secondary containment. Tank level monitoring is how you evidence control and catch losses before they become reportable pollution incidents.

The core requirements are blunt. Under the 2001 Regulations, a fixed tank must sit inside a secondary containment system holding at least 110% of its capacity, or for multiple tanks, 110% of the largest or 25% of the aggregate, whichever is greater. Government guidance on storing oil at a home or business confirms the rules bite at 201 litres or more for businesses and public buildings, and 3,501 litres or more for homes, with drums needing 25% containment.

Enforcement is real: the Environment Agency can serve an anti-pollution works notice compelling you to upgrade a non-compliant store, and prosecution follows pollution. A live tank level monitoring feed strengthens your position on every front. Reconciling metered dispensing against measured level exposes leaks a visual bund check misses; delivery-time overfill alarms protect the moment when most spills happen; and a timestamped level history shows a regulator you exercised due diligence.

Wales and Scotland run parallel regimes with the same 110% containment principle, so a monitoring policy built for England transfers across a UK estate. For chemical and effluent tanks, the same alerts underpin COMAH and discharge-consent duties, and sites in oil and gas, agriculture and water treatment reuse the identical stack.

FAQ: people also ask about tank level monitoring

How accurate are ultrasonic tank level sensors?

Good ultrasonic tank level monitoring sensors hold plus or minus 1% of full scale with 1 mm resolution; the EM500-UDL specifies exactly that across its 0.25 to 10 m variants. Built-in temperature compensation matters because the speed of sound shifts with air temperature inside the tank headspace.

How long do LoRaWAN tank sensors last on battery?

The EM500-UDL is rated for 10 years at a 10-minute reporting interval at 25 degrees Celsius from its replaceable 19,000 mAh Li-SOCl2 battery. Slower cadences extend that; sub-zero temperatures and very frequent alarms shorten it. Either way, you fit it once and forget wiring entirely.

Can tank level monitoring detect fuel theft?

Yes. A change alarm flags any abnormal drop between readings, so a few hundred litres siphoned overnight raises an alert within minutes rather than at the next delivery. With NFU Mutual reporting fuel theft doubling in 2022, out-of-hours drop alerts are the cheapest deterrent a rural site can buy.

Do I need a SIM card or Wi-Fi at every tank?

No. Each sensor talks LoRaWAN to a shared gateway up to 10 km away in line of sight, and only the gateway needs a backhaul connection over Ethernet or cellular. That is why remote tanks, bunds and field reservoirs with no power or connectivity are exactly where LoRaWAN tank level monitoring wins.

Which tanks can I monitor: fuel, water, chemical or waste?

All of them, by matching the sensor to the medium: ultrasonic for diesel, heating oil, AdBlue and waste oil; submersible pressure for deep water and boreholes; laser time-of-flight for narrow or baffled vessels; radar for hot, vaporous or pressurised chemicals. The LoRaWAN network and dashboard stay identical throughout.

Does monitoring make me compliant with the oil storage regulations?

Not by itself. The 2001 Regulations demand physical measures, principally 110% secondary containment on stores over 200 litres. Tank level monitoring complements them: it proves the tank is behaving, catches overfills during delivery and gives you the level history that demonstrates due diligence if the Environment Agency ever asks.

Where do you start?

Start with your highest-consequence tank: the generator day tank that must never run dry, the heating oil tank that keeps getting stolen from, or the chemical store next to a drain. One sensor and one gateway prove the value of tank level monitoring in a fortnight, and the same gateway then absorbs every other tank on site.

Browse LoRaWAN level sensors and gateways in the Indiott shop, or tell us your tank sizes, liquids and site layout and request a quote. We will spec the sensor variants, gateway placement and alert thresholds for you.