Water pressure and flow rates
Understanding your water system and choosing compatible bathroom products.
At a glance
Quick Checklist
Key points at a glance
- 1Know your system: combi, gravity, or unvented
- 2Measure pressure before buying products
- 3Low pressure needs specific taps/showers
- 4High flow showers need adequate supply
- 5Consider a pump if pressure is poor
Questions to ask your installer
Take these to your next conversation with your fitter
- 1What's my current water pressure and flow rate?
- 2Is my system suitable for the products I want?
- 3Do I need a pump to achieve good shower pressure?
- 4Will the new bathroom affect pressure elsewhere in the house?
- 5What's the cost of upgrading my water system if needed?
- 6Can the hot water cylinder cope with a large bath?
💡 Tip: A good installer will welcome these questions. If they dismiss them, that's a red flag.
💡Myth vs Reality
Common Myth
"Good showers are only possible with high pressure"
The Reality
Modern low-pressure showers and pumped systems can deliver excellent results.
Common Myth
"Combi boilers are always worse for showers"
The Reality
Good combis can deliver excellent pressure. It depends on the specific model and gas supply.
What to look for
- •System type: combi boiler, gravity tank, or unvented cylinder
- •Pressure: measured in bar (0.1-3+ bar typical)
- •Flow rate: litres per minute (l/min)
- •Product compatibility - most state minimum pressure required
Common mistakes
- •Buying products without knowing your pressure and flow
- •Expecting a rainhead shower on a gravity system without a pump
- •Not considering that multiple outlets reduce pressure
- •Assuming mains pressure is always adequate
Quality considerations
- •Understanding your water system prevents expensive mistakes
- •Some products are specifically designed for low pressure systems
- •A good shower experience depends on pressure AND flow rate
- •Consider future-proofing if you might add more bathrooms
Planning a bathroom right now?
Submit your project for a free 3D layoutNo obligation. Planning support is always free.
Trusted by verified installers
Our guides are shaped by real installer experience and the most common homeowner mistakes — without pushing any specific brand or purchase.
The Plan My Bathroom Promise
Plan with clarity first. Products and partners are always optional.
No obligation to purchase
Planning support is always free
Planning-first approach
Get clarity before making decisions
Verified professionals
Optional introductions when you're ready
Transparent guidance
Honest advice, no hidden agendas
Found this helpful? Share it:
This guide is written to help you make informed decisions, not to sell you anything. Always discuss your specific situation with a qualified installer.