Salamander (and others faik) do a range of "boost" pumps that might help. Depends how pathetic the flow is.

Tank on the roof like they do elsewhere in the world.

When I did a Water Regulations course some years ago we were told that fitting a booster pump drawing water directly from the mains, other than a fire pump, was not permissible. 

That makes sense as it could result in neighbours being deprived of a water supply and the mains may be contaminated for example water being drawn back in from a hose pipe. 

These days however they seem readily available, whether that makes using them or not acceptable is another matter. 

Electric showers with a built in pump are available and probably the simple solution. Not certain if they are "allowed" or not, but widely sold by reputable suppliers. Can be supplied from a low level storage cistern, the cistern has to be above the shower heater and pump unit, but the spray outlet can be above the cistern.

The Water Supply and Fittings Regulations 1999, state that you can boost mains water for domestic use with suitably small pumps, as long as the final pumped mains water flow does not exceed 12 litres per minute (l/min). In cases where a household does experience a flow rate much lower than 12l/min the incoming mains water flow can be usefully increased using a mains booster pump. Screwfix and others do a number of WRAS compliant pumps designed precisely for the purpose.

Larger pumps and supplies to multiple properties require the express consent of the water supplier  along with a whole list of other things, like baths larger than 230 litres, bidets with flexible hoses, pools and so on - all in section 5 and the associated table.

Mike

So, I wonder what happens if a dozens chalets on the same mains' water pipe supply all turn on booster pumps at once?

Z.

If the flow rate is less than 12 litres per minute the first thing to do is to ask the water board to investigate.

They will only check flow and pressure at the kitchen sink assuming it has the first cold water tap on the consumers installation.

A water board inspector once turned up just after I had removed the kitchen sink and tap, he got into quite a fluster about testing at the outside tap when I suggested it.

Presumably the water board will refuse to check the water supply at individual chalets or caravans unless they are supplied directly from the water board system rather than through a privately owned distribution system.

Yes Anglian Water has checked the pressure and said that nothing can be done to improve the water pressure, as the pipes are small, the chalets remote and high demands during the holiday season causes the pressure loss.

Z,

Remember there’s a difference between flow rate and pressure.

For an electric shower you need to measure the running pressure with the water flowing, not the static pressure without any flow.

Do you even know if the pipework is even supplied directly from the mains, there could possibly be an onsite storage tank which actually feeds the supply to the chalets.