I stumbled upon this post Water usage sensor - #22 by rasika by @rasika
It was more or less the same problem.
Now I can try to make my numbers correct.
Thanks
New code:
sensor:
- platform: pulse_counter
pin: GPIO12
update_interval : 60s
name: "water pulse"
id: water_pulse
- platform: pulse_meter
pin: GPIO12
name: "Water Pulse Meter"
unit_of_measurement: "liter/min"
icon: "mdi:water"
total:
name: "Water Total"
id: water_total
unit_of_measurement: "liter"
- platform: copy
source_id: water_total
name: "Water Meter Total"
icon: "mdi:water"
unit_of_measurement: "m³"
id: water_meter_total
accuracy_decimals: 3
device_class: water
state_class: total_increasing
filters:
- multiply: 0.001
- platform: template
name: "Water Usage Liter"
id: water_flow_rate
accuracy_decimals: 1
unit_of_measurement: "l/min"
icon: "mdi:water"
lambda: return (id(water_pulse).state / 75);
update_interval: 6s`