How Steve Murch's Off-Grid Water Tank Monitor Works

Steve Murch's off-grid water tank monitor is a two-node ESP32 LoRa system: one device at the wellhouse measures the tank, and a second device elsewhere receives and displays the reading over a long-range, low-power radio link. That architecture is the core of the project as he describes it — "a water tank measuring system using two ESP32 LoRa devices" for an off-grid wellhouse. The published summary does not specify the sensing method, the display hardware, or the exact firmware, so the details below separate what the project states from the general engineering that a build like this requires.

What the project actually specifies

From the site's own description, three things are confirmed:

• Purpose: measure the water level in a tank serving an off-grid wellhouse.
• Radio link: two ESP32 LoRa devices, i.e. ESP32 microcontrollers paired with LoRa transceivers.
• Topology: a two-node system, which implies one node at the tank and one node where the reading is consumed.

Everything else — sensor type, power source, enclosure, display — is not stated in the available material and should be treated as design choices rather than documented facts.

Why a two-node LoRa design makes sense here

An off-grid wellhouse is typically far from the house, often without mains power or Wi-Fi. That combination rules out most simple approaches:

The trade-off is bandwidth: LoRa is designed for small, infrequent payloads. A tank level is a single number, so that limitation costs nothing here.

How the measurement and transmission chain works

A build of this shape follows a predictable chain, and each link is where a project like this succeeds or fails.

1. Sensing the level

The tank level has to become an electrical signal. Common options for a DIY tank monitor include an ultrasonic distance sensor mounted above the water, a pressure sensor at the tank outlet, or a float/reed switch arrangement. The choice determines accuracy, cost, and how much maintenance the sensor needs. The published project description does not name which method was used.

2. Reading it on the tank-side ESP32

The ESP32 samples the sensor, converts the raw value into a level (or a percentage of full), and packages it into a small message. Because the payload is tiny, it fits LoRa's constraints easily.

3. Sending over LoRa

The tank-side node transmits the reading to the second ESP32 LoRa device. LoRa's range depends heavily on antenna, terrain, and obstacles, but its whole purpose is covering distances that Wi-Fi cannot — which is exactly the gap between a wellhouse and a house.

4. Receiving and presenting

The second node receives the packet and does something useful with it: display the level, trigger an alert when the tank is low, or forward the value onward. The project summary stops at "how it works" without naming the receiving end's output.

What to verify if you build your own

If you're using this project as a reference, these are the points that decide whether your version works:

• Sensor choice vs. tank geometry. An ultrasonic sensor needs a clear path to the water surface; a pressure sensor needs a port at the right height. Match the sensor to the tank, not the other way around.
• Power budget. If the wellhouse has no mains power, the tank-side node's sleep/wake schedule drives battery life more than anything else.
• Link margin. Test the LoRa link at the real distance and through the real obstructions before committing to the installation.
• Failure behavior. Decide what the receiver shows when a packet is missed, so a dropped message doesn't look like an empty tank.

The takeaway

The design is deliberately minimal: one ESP32 LoRa node measures, one receives, and the radio link solves the off-grid distance problem that Wi-Fi can't. The published material confirms the two-node ESP32 LoRa architecture and the off-grid wellhouse context; the sensor, power, and display specifics are left to the builder. For a fuller picture, the original project write-up on stevemurch.com is the place to check for the parts list and firmware details.