We have taps and dip tank however the council have informed us that they are having to check all the allotment set ups for legionella as it is a legal requirement and we may loose our dip tanks.
We are not allowed to permanently connect a hose to the tap we have however fitted a hoselok type connector using a short pipe and a non return end. Any hoses fixed directly to taps are cut off by the parks department.
2 or 3 way splitter are then used to attach based on how many people want to water. There are a number of hoses that all go up to the taps, and they are attached by the individual when they want to water.
We are not allowed to use un attended ends like sprinklers, although we have one guy who does.
I have a watering system set up along my allotment so I have hoses with guns every other set of beds so I don't have to drag a hose around so a main line down the path and four offsets with one hose and gun so I can go either side of the path. Hose cut for longest reach required due to shape of plot
I use pop bottles with end caps and holes made with mapping pins sunk into the beds so that I water mainly at depth and make the root go find the water. Planting using weed membrane with planting holes sorts out my spacing, lets rainwater in but also acts like a mulch to keep down evaporation.
For me watering when required needs about being effective and quick, I don't have all day to faff around.
I also have a blue water butt on the shed - two water butts on the greenhouse which can be connected to the system. Plus I have comfrey tea and nettle tea in water butts on draft for use with a watering can when feeding rather than watering.