Low water pressure is one of those problems that people learn to live with rather than fix. The shower that never quite feels strong enough. The hot tap that takes a long time to fill a bowl. The washing machine that runs longer than it should because it is filling slowly. Each of these inconveniences is accepted as normal until someone mentions that their own house does not work this way, and then the frustration arrives all at once.

A qualified plumber in Dursley can diagnose the cause of low water pressure and, in most cases, improve it. The right solution depends on what is actually causing the problem, and the causes vary more than most homeowners realise. This guide covers the most common reasons for low pressure in Dursley properties, the options available to address each one, and what the process of diagnosis and improvement looks like in practice.

Understanding Water Pressure: What Is Normal and What Is Not

Water pressure in the UK is measured in bars. Severn Trent Water, which supplies the Dursley area, is required by law to maintain a minimum mains pressure of 0.7 bar at the point where the supply enters a property. In practice, most properties receive between 1 and 3 bars at the mains connection. What arrives at individual taps and showers depends on the internal plumbing system from that point.

Normal operating pressure for a combi boiler or mains-fed shower is typically between 1 and 1.5 bar. Gravity-fed systems, which use a cold water cistern in the loft to supply pressure by height difference, deliver lower pressures, often between 0.1 and 0.3 bar depending on the height of the cistern above the outlets. A gravity-fed shower that feels weak may be performing normally for its system type, rather than indicating a fault.

Common Causes of Low Water Pressure That a Plumber Can Fix

Let’s break down the most frequent causes and what can be done about each.

Partially Closed Isolation Valves or Stopcocks

A stopcock or isolation valve that is not fully open restricts flow through the supply. This is more common than it sounds. A valve that was partially closed during a previous repair and never fully reopened, or one that has stiffened with age and cannot be turned to the fully open position, can significantly reduce pressure throughout the property. A plumber will check all accessible valves as part of a pressure investigation and replace any that cannot be operated correctly.

Faulty or Incorrectly Set Pressure Reducing Valve

Many properties have a pressure reducing valve, or PRV, fitted on the incoming supply to protect internal pipework and appliances from high mains pressure. A PRV that is set too low reduces pressure throughout the property. One that has failed may restrict flow even if the set point appears correct. Adjusting or replacing a PRV is a straightforward job for a qualified plumber and can produce a noticeable improvement in pressure at relatively low cost.

Limescale Accumulation in Supply Pipes

In areas with moderately hard water, internal limescale in hot water supply pipes reduces the effective bore over time. Flow rate drops gradually, which is easy to miss as you adapt to the change. A plumber can assess the likely extent of scale accumulation based on the age of the pipework and the local water hardness, and advise on whether descaling or partial pipe replacement is the more practical option for the specific installation.

Undersized Supply Pipework

Older properties were sometimes plumbed with 15mm supply pipes throughout when current practice would use 22mm for main runs. An undersized pipe can supply one outlet adequately but struggles when two or more outlets run simultaneously. Pressure drops noticeably when the shower runs while a tap is on elsewhere. Upgrading specific sections to larger bore pipework addresses this at the points where demand is highest.

Pump Solutions: When and How a Plumber in Dursley Can Install One

Where the mains supply pressure is adequate but the internal system cannot deliver it at the outlets, a pump can make a meaningful difference. There are two main types: shower pumps and whole-house booster pumps.

A shower pump fits on the gravity-fed supply to the shower and boosts the flow at that specific outlet. These are relatively inexpensive, fitting between £150 and £400 installed, and work well where the shower is the primary low-pressure complaint. They require a gravity-fed hot and cold supply to work correctly. They cannot boost pressure from a mains-fed system or from a combi boiler supply.

A whole-house booster pump fits on the incoming mains supply and increases pressure throughout the property. These are more expensive, from £400 to £1,000 installed depending on the unit, and are subject to Water Regulations. Severn Trent and other water suppliers have rules about what can be connected to the mains supply. A qualified plumber in Dursley will advise on whether the intended installation meets those requirements before proceeding.

What to Expect from a Water Pressure Assessment

A plumber assessing water pressure in your home will follow a structured process. Here is roughly what that involves:

• Measuring mains pressure at the incoming supply point using a pressure gauge
• Checking the condition and position of the main stopcock and any isolation valves
• Measuring flow rate and pressure at individual outlets, including taps and showers on both hot and cold supplies
• Identifying where the largest pressure drops occur between the supply point and the outlets
• Assessing the system type, mains-fed combi, gravity-fed, or unvented cylinder, to understand what improvements are possible
• Advising on whether the cause is the mains supply, the internal system, or a specific component

A written report of findings with costed options is worth requesting before committing to any work. Some pressure problems have inexpensive solutions. Others require more involved work. Understanding the options and their costs before starting means you make an informed decision rather than agreeing to the first remedy suggested.

Frequently Asked Questions

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