1. What is Water Efficiency Calculation?

The water efficiency calculation for new dwellings is required by Part G of building regulations. It ensures that water consumption does not exceed 125 liters per person per day, promoting sustainable water use in residential buildings.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( \text{fixture\_consumption} \) — Total water consumption from all fixtures (l/person/day)
• \( 5 \) — Allowance for external water use (l/person/day)

Explanation: The calculation sums all fixture water consumption and adds a fixed allowance for external use to determine total water efficiency.

3. Importance of Water Efficiency

Details: Meeting water efficiency standards is crucial for sustainable development, reducing water consumption, and complying with building regulations Part G requirements.

4. Using the Calculator

Tips: Enter the total fixture consumption in liters per person per day. The calculator will add the 5 l/person/day external use allowance and check compliance with the 125 l/person/day limit.

5. Frequently Asked Questions (FAQ)

Q1: What is included in fixture consumption?
A: Fixture consumption includes water usage from toilets, showers, baths, taps, and any other water-using fixtures in the dwelling.

Q2: Why is there a 5 l/person/day external allowance?
A: This accounts for external water uses such as garden watering, car washing, and other outdoor water consumption.

Q3: What is the maximum allowable water consumption?
A: The total water consumption must not exceed 125 liters per person per day to comply with Part G regulations.

Q4: How is per person consumption calculated?
A: Consumption is calculated based on standard occupancy assumptions for the dwelling type and size.

Q5: Are there different requirements for different dwelling types?
A: The 125 l/person/day standard applies to all new dwellings, though calculation methods may vary slightly for different fixture types.