Why your water pressure might be low – Part 2
Assuming that your supply from the mains is ok, as described in part 1, we now look at the plumbing inside your home and try and find the reasons why you have poor flow rates.
Most of the problems are caused by bad plumbing practises, incorrect choice of fittings or both. For example:
The customer complained about low water pressure to the whole house, the reason is fairly obvious… did you spot it? When the meter installer cut into the supply to fit the meter inside the property (usual cheapskate method, rather than dig the pavement up) he for some bizarre reason fitted next to the drain cock (directly above the meter) a 15mm isolator or ball valve.
Not a full flow valve, but one with an internal diameter of around 6mm. So we have gone from a 15mm incoming feed to a 6mm restriction before any other pipework, totally unforgivable.
The pipework was altered as part of a kitchen and boiler replacement and as we see in the right hand picture, we now have an uninterrupted flow for the water (apart from a couple of bends and T’s but this pipework all to be boxed in). A few more of these were found to be fitted on hot and cold water pipes during investigation.
Below is a selection of various fittings often found in homes and often misused or fitted in inappropriate situations. Click images for larger view.
If a small bore isolator valve is fitted to high pressure taps on a low pressure system, water is reduced to a dribble. Likewise if fitted on supply to loft tanks (I see it often) tank takes ages to fill. Gate valves are not suitable for mains pressure water, often see them fitted. Time and again I come across incorrect fittings for a particular situation. The other thing to consider is as well as restricting water flow, a small bore fitting used for the wrong purpose can create noise.
The main reason many “plumbers” use incorrect fittings is down to cost and time. A cheap isolator valve can be less than £1, a decent full bore is around £6. But the results can make a big difference to performance, all for a few quid. Cheap valves usually fail after a few months (or even days!) as well.
Hopefully this has given you a few pointers as to where your low pressure problems may lie.
If you have low water pressure problems, or any other plumbing related problems, give me a call or send a message.