A guide to water pressure, critical when choosing your tap.

Generally speaking most properties in the UK have a cold water supply that is mains fed and usually High Pressure. The Hot Water pressure however can vary, it is dependent on the type of system used to generate and provide the Hot water to the Kitchen Tap.

The performance of any tap is determined by the type of tap, and it's compatibility with your plumbing supply. Most plumbing systems in the UK providing hot water, fall into two categories: Low/ Medium Pressure (Gravity Feed Supply), and High Pressure Systems.

The most common system in over 75% of UK homes is Gravity Feed Supply. This type of system has a high mains pressure, cold water supply connected direct to the kitchen tap, with a supply to a cold water storage/feed tank, (usually found in the loft space) the cold water is then fed by gravity from the tank to the hot water storage cylinder (usually found in an airing cupboard in the bedroom, bathroom or in a cupboard accessed from the landing) the hot water is usually generated by a boiler or in some cases a form of immersion heater. The hot water is stored in the cylinder and fed to the downstairs taps by gravity. The actual pressure of the gravity fed hot water is determined by the height of the bottom of the cold water storage/feed tank in relation to the height of the kitchen tap, the term for this is "head of water"

The higher the tank from the kitchen tap the greater the head of water, so the greater the pressure, ie. 1 metre head = .1 bar, 5 metres head = .5 bar, 10 metres head = 1 bar

The term Head of water means the vertical height from the kitchen tap to the underside of the cold water storage tank, The conversion from Bar to head is based on the assumption that the tap is situated directly in line below the storage tank. In reality this is very rarely the case and where long pipe runs occur across the property, from storage tank to the tap, the result is poor hot water performance.

To obtain sufficient pressure on a traditional gravity feed system to run an average High pressure tap with a 1 bar recommended minimum pressure you would have to have a 4/5 story building or 10 metres / (32.5 feet) head.

To run an average Medium/High pressure tap with a .5 bar recommended minimum pressure you would have to have a 3 story building or 5 metres / (16.25 feet) head. (Or a Booster Pump - see below)

A lot of new properties have High Pressure hot water systems fitted from new, mainly from combination boilers, they are also becoming more popular in the replacement market. Pressure systems provide a balanced and pressurized hot and cold water supply.

All taps will work with High Pressure hot water systems, but not necessarily with medium/low pressure Gravity feed supply, so it is important to check the specification of the tap before buying.

Please feel free to browse through the different manufacturers ranges of taps, if you’re not sure of the suitability of your preferred choice, please do not hesitate to ring us.

If you’re preferred tap has a high pressure requirement but you have a low pressure system, a booster pump can be fitted under the sink with a minimum amount of plumbing needed.