Low water pressure complaints fall into two categories: a true mains-pressure problem where the incoming supply is restricted or undersized, and a perceived-pressure problem where the mains is fine but one or more fixtures are choked, throttled, or fed by an undersized internal run. Thames Water provides a minimum 1 bar static pressure at the boundary stop-cock under their levels-of-service obligation, and most central-London supplies deliver 2 to 3 bar dynamic at the kitchen tap. Less than that usually points to a fault inside the property: a partially closed valve, a scaled-up pressure-reducing valve, a kinked plastic supply pipe, or a hidden leak between the boundary box and the first internal draw-off.
Our diagnostic visit gauges pressure and flow at five separate test points: the boundary stop-cock, the internal stop-tap, the kitchen cold tap, the first-floor bathroom basin, and the shower head. We measure static pressure (taps closed) and dynamic pressure and flow (taps open) with a calibrated gauge and flow cup so the results are comparable to Thames Water's published service levels. From those readings we can isolate the fault in one visit, whether it is a failed PRV, a part-closed stop-tap, a hidden leak on a buried MDPE supply, or a scaled-up internal run that needs replacing. The report includes the readings, the diagnosis, and a fixed quote for the remedial work.
Where this service applies
- Whole-house pressure drop affecting every cold outlet from kitchen to upstairs bathroom
- Combi boiler running cold or short-cycling because hot-side flow falls below the minimum trigger
- Shower flow weak even though the basin tap nearby runs normally
- Upstairs taps weak compared to ground floor, classic head-loss or partial valve closure
- Recent water-bill spike pointing to a hidden mains-supply leak on the buried MDPE run
- Pressure-reducing valve fitted and now passing too little flow, common on older PRVs with scaled diaphragms
- Newly purchased property where the supply pressure is unknown and a baseline survey is needed
- Flat conversion with shared rising main where pressure varies with neighbour demand
- Commercial premises with documented pressure obligations to insurer or landlord
How we deliver
No surprises, no upselling. The exact path every job follows.
- 1
History and symptom map
We log when the drop happened, which fixtures are affected, whether neighbours report the same, and any recent works (kitchen refit, new boiler, building work) that might point to the cause. - 2
Boundary-stop-cock baseline
Calibrated pressure gauge fitted at the boundary box (or the closest accessible test point on the rising main) to read incoming static and dynamic pressure from Thames Water's network. - 3
Internal stop-tap reading
Pressure read on the house side of the internal BS1010 stop-tap to confirm the valve is fully open and the line between the boundary box and the property is not throttled or leaking. - 4
Per-fixture flow and pressure test
Kitchen cold tap, first-floor basin, shower head, and any other reported weak outlet measured for static pressure and dynamic flow rate (litres per minute) with a calibrated flow cup. - 5
Hidden-leak check on the supply run
Stop-tap closed and pressure held on the line for a 15-minute drop test. A drop with no fixture use points to a leak on the buried MDPE supply or the internal cold run, and we follow up with acoustic and thermal trace. - 6
PRV and check-valve inspection
Where a pressure-reducing valve or single check valve is fitted, the unit is stripped and inspected for scaled diaphragm, perished O-ring, or partial closure. Replacement is a 30-minute swap on most domestic PRVs. - 7
Written report and remedial quote
Readings logged on a one-page survey sheet with photographs of test points, the diagnosis stated plainly, and a fixed quote for the remedial work. Suitable for landlord, insurer, or solicitor submission.