Best RV Tank Monitoring Sensors (2026)
The Sensor Landscape in 2026
RV tank sensors have improved significantly in the last few years. Ultrasonic and capacitive sensors have replaced the unreliable resistive probes that plagued RVers for decades. Here are our picks after testing the leading options.
Best Propane Sensor: Mopeka Pro Check
The Mopeka Pro Check (~$45) uses ultrasonic measurement to read propane levels through the bottom of the tank. It mounts magnetically, runs on a CR2032 battery for about a year, and broadcasts over BLE to the Mopeka app or compatible displays.
- Accurate to 5% across the full range
- No wiring, no drilling, no contact with propane
- Works with standard DOT cylinders and ASME tanks
- Battery lasts approximately 12 months
Mopeka Pro Check on Amazon (~$45)
Best Water/Waste Sensor: Mopeka Universal
The Mopeka Universal (~$70) applies the same ultrasonic technology to water and waste tanks. It mounts externally on the bottom of the tank, so there is no contact with tank contents. This eliminates the fouling problem that kills traditional in-tank sensors within a year or two.
Mopeka Universal on Amazon (~$70)
Budget Option: Stock Resistive Senders + ADC
If your RV already has working 3-wire resistive tank senders, you can read them directly with a Raspberry Pi and an ADS1115 analog-to-digital converter (~$4). The ADS1115 reads the voltage from each sender and converts it to a tank level percentage. This is the cheapest path to digital tank monitoring if your existing hardware still works.
The downside: resistive senders in waste tanks foul over time. This is a good bridge solution, not a permanent one for black tanks.
Best Temperature Sensor: Xiaomi LYWSD03MMC
At roughly $6 per sensor, the Xiaomi LYWSD03MMC is the best value sensor we have ever tested. Flash it with ATC firmware (free, takes 2 minutes over BLE) and it broadcasts temperature and humidity data as open BLE advertisements that any BLE gateway can pick up.
- Temperature accurate to 0.3 degrees C
- Humidity accurate to 3% RH
- CR2032 battery lasts 6-12 months with ATC firmware
- Use for: fridge, freezer, engine room, basement storage, exterior
Xiaomi LYWSD03MMC on Amazon (~$6)
Tire Pressure: Generic BLE TPMS
Generic BLE TPMS sensors run about $30 for a set of 4. They screw onto the valve stem and broadcast pressure and temperature over BLE. Accuracy is acceptable (within 1-2 PSI), and they provide early warning of slow leaks or temperature spikes. Battery life varies by brand but is typically 12-18 months.
BLE TPMS sensors on Amazon (~$30/set)
Comparison Table
| Sensor | Price | Protocol | Battery Life | Accuracy | Best For |
|---|---|---|---|---|---|
| Mopeka Pro Check | ~$45 | BLE | ~12 months | 5% | Propane tanks |
| Mopeka Universal | ~$70 | BLE | ~12 months | 5-10% | Water/waste tanks |
| ADS1115 + Pi | ~$4 | I2C (wired) | N/A (powered) | Varies | Existing resistive senders |
| Xiaomi LYWSD03MMC | ~$6 | BLE (ATC fw) | 6-12 months | 0.3C / 3% RH | Temp/humidity anywhere |
| Generic BLE TPMS | ~$30/4 | BLE | 12-18 months | 1-2 PSI | Tire pressure monitoring |
Integration Note
None of these sensors talk to each other natively. Each has its own app. If you want a unified dashboard, you will need a BLE gateway (Raspberry Pi with BlueZ, or an ESP32) that collects all the BLE advertisements and feeds them into a dashboard like Grafana, Home Assistant, or a custom web UI. See our RV Battery Monitoring article for more on integration approaches.
