The water counter on ESP8266 for Arduino IDE
You need to use mosquitto server, mqttwarn, perl and sqlite3.
A mini wifi board with 4MB flash based on ESP-8266EX - Wemos D1 mini https://wiki.wemos.cc/products:d1:d1_mini
Micro SD Card Shield for Wemos D1 mini - https://wiki.wemos.cc/products:d1_mini_shields:micro_sd_card_shield
Lithium (LiPo) Battery shield, charging & boost for Wemos D1 mini - https://wiki.wemos.cc/products:d1_mini_shields:battery_shield
A triple(x3) Base for Wemos D1 mini - https://wiki.wemos.cc/products:d1_mini_shields:tripler_base
Chip MC14490 Hex Contact Bounce Eliminator - http://www.west-l.ru/uploads/tdpdf/oh646060.pdf
Resistor 12kOm 0.125W for Battery shield (for external power control, see https://github.com/slacky1965/watermeter/blob/battery/doc/images/Wemos1.jpg)
Lithium (LiPo) Battery 18650 2600mAh 3.7V