Try water level monitor project with your hardware (Arduino, ESP32, ESP8266). There are several sample source codes available in Arduino Core, or ESP-IDF. There are also many available transmission technologies for direct or indirect writing to the portal (PHY Ethernet, WiFi, NB-IoT, LoRa, LoRaWAN, BLE Beacon): https://martinius96.github.io/hladinomer-studna-scripty/en/