Water Supply

Introduction

Water is a public utility and considered an essential service. Water is delivered by a public or private utility company to buildings for various uses including consumption (drinking), sanitation, and various other household uses. The cost of water is typically billed based on consumption, similar to electricity and natural gas.

With water, there are various design considerations to factor into the design of systems and how they integrate within a structure. When water supply systems are compromised, they have deadly consequences.

Water Pressure

PSI Pounds per Square Inch

Water comes into a building at a certain PSI (Pounds per Square Inch). This will vary by municipality, location (distance) away from supply, elevation of building, and other factors. Each fixture will come with its own design and features that may reduce water pressure to a more appropriate level for the function.

Water from city mains will be delivered to the building after treatment/cleaning. If pressure delivered is too high, then a reducing valve should be installed at the building point.

• City mains = 50 PSI typically (40-80 PSI expected)
• Water flush = 10 to 20 PSI in order to function.
• Shower = 12 PSI for comfort

Static Pressure Head

Water pressure increases with water depth, this is a simple concept that you can relate to the ocean. Static head pressure is water pressure expressed as a unit of length. Water pressure = Height of pressure.