top of page
louw98

How to Calculate Grey Water Harvesting Potential Using SANS 10400 / SANS 10252 Guidelines, Part 2


💧 How to Calculate Grey Water Harvesting Potential Using SANS 10400 / SANS 10252 Guidelines 🌱


Estimating how much grey water you can harvest in homes and commercial offices is an essential step in managing water use effectively. Here’s a simplified guide based on SANS 10400 (Building Regulations) and SANS 10252 (Water Supply Standards) to help you calculate your grey water potential:


Identify Grey Water Sources

According to SANS 10400 / SANS 10252, grey water typically comes from:

  • Homes: Showers, baths, hand basins, washing machines, and kitchen sinks.

  • Offices: Hand basins, kitchen sinks, and laundry areas.


Calculate Average Water Usage

SANS 10252 specifies recommended water usage for various fixtures:

  • Shower/Bath: ~40-60 liters per person per day

  • Hand Basin: ~7-12 liters per person per day

  • Washing Machine: ~80 liters per load

  • Dishwasher (optional): ~12-15 liters per load


Multiply by Occupancy or Usage Frequency

Multiply the water usage by the number of occupants or by daily usage:

  • Homes Example:

    A family of 4 using the shower once per day would generate:

    4 people x 50 liters = 200 liters of grey water per day.

  • Offices Example:

    An office with 50 staff using hand basins once daily:

    50 people x 10 liters = 500 liters of grey water per day.


Apply Recovery Factor

Grey water systems typically recover between 50-80% of the total grey water used, as not all water can be reused (depending on filtration and system setup).

  • Homes Example:

    For 200 liters of grey water/day, at a recovery rate of 70%, you would yield:

    200 liters x 0.7 = 140 liters of usable grey water per day.

  • Offices Example:

    500 liters/day x 0.7 recovery = 350 liters of usable grey water per day.


Annual Grey Water Yield

To estimate the yearly grey water harvested, multiply the daily yield by 365 days:

  • Homes Example:

    140 liters/day x 365 days = 51,100 liters/year.

  • Offices Example:

    350 liters/day x 365 days = 127,750 liters/year.


Why Use SANS Guidelines?

  • SANS 10400 & SANS 10252 ensure that your water usage calculations meet local building regulations and water efficiency standards.

  • These guidelines help you accurately estimate water needs, reduce wastage, and ensure safe and sustainable water reuse practices.


Conclusion:

Using SANS standards allows you to precisely calculate your grey water potential, helping you to design an efficient system that conserves water, cuts costs, and aligns with sustainability goals!



 DFR Engineers

012 546 7574 | 082 573 4603

Follow us on LinkedIn

20 views0 comments

Comentarios


bottom of page
Subscribe on LinkedIn