In a typical domestic water system, domestic hot water is produced by heating domestic cold water, which is then distributed to taps, showers, and other appliances. There are two main types of systems: direct and indirect. Direct systems supply cold water directly from the mains to the hot water cylinder or combi boiler, while indirect systems use a cold water storage tank before heating. 

Domestic Hot Water Systems:

• Direct Systems:

  These systems are more common in modern homes. Mains water is directly fed to the hot water cylinder or combi boiler, which heats it before it's distributed to taps and showers. 

• Indirect Systems:

  These systems use a cold water storage tank (cistern) in the loft, where cold water is stored and then fed to the hot water cylinder for heating. This stored water is then distributed to taps and showers. 

• Low Pressure Gravity Systems:

  These are often found in older homes and rely on gravity to provide water pressure. The cold water tank (cistern) in the loft supplies water to the hot water cylinder (or calorifier) on the first floor, which then distributes hot water. 

Domestic Cold Water Systems:

• Direct Systems:

  Cold water is supplied directly from the mains to all cold outlets, including taps, showers, toilets, and washing machines. 

• Indirect Systems:

  These systems rely on a cold water storage tank (cistern) in the loft to store and distribute cold water. 

Key Considerations:

• Mains Pressure:

  Direct systems can be noisy and may not function if mains water pressure is low or the supply is interrupted. 

• Storage:

  Indirect systems require space for a cold water storage tank, which can be bulky. 

• Pressure:

  Low-pressure gravity systems have lower water pressure, which may require booster pumps. 

• Safety:

  Proper installation and maintenance are crucial to ensure the safe and efficient operation of both hot and cold water systems.