To find out the flow rate of your taps is very easy all you need is a bucket with the litre measurements on the side.
For the most accurate measurement for irrigation you should cut a piece of old hose to the length of the furthest point you would like to irrigate in your garden and from that point is where you should put the bucket.
Now turn the tap on and start timing how long it takes to fill the bucket up to the 10 Litre mark, if possible.
Let’s say that took 30 seconds, so now we know that every minute you can have 20 Litres. So, all you must do is multiply 20L x 60(minutes) = 1200L/ph. and now you know you can have 1200 Litres of water every hour from that point.