Rainwater Harvesting: Estimating Potential Savings

In Cape Town, the challenges of a rising cost of living are palpable, affecting every aspect of daily life. One area that hits homeowners hard is the escalating water bills, a burden on both finances and the environment. At Devco Plumbing, we believe in empowering South Africans to combat these challenges through a sustainable solution: rainwater harvesting.

Estimating Potential Water Savings:

The amount of water that can be saved through rainwater harvesting depends on various factors, including the local climate, the size of your roof, and the efficiency of your collection system. However, we can provide a general guideline to help you estimate potential savings.

Rainfall:

The specific climate of your location plays a crucial role in estimating potential water savings. For instance, in Fish Hoek, where the average amount of annual precipitation is 621 mm, this becomes a key factor in determining the viability of rainwater harvesting.

Roof Area:

Measure the catchment area, i.e., the size of your roof where rainwater can be collected. This is typically the area that slopes towards your gutters. The larger the roof, the more rainwater you can collect.

Collection Efficiency:

Consider the efficiency of your collection system. Factors such as the type of gutters, the presence of debris guards, and the condition of the roof can impact efficiency.

Storage Tank Size:

Determine the size of your storage tank. The larger the tank, the more water you can store for later use during dry periods.

Formula for Estimating Water Harvesting Potential:

Potential Water Harvested = (Average Annual Rainfall) x (Roof Area) x (Collection Efficiency)

Example:

Let's say you have an average annual rainfall of 621mm, a roof area of 1,000 square feet, and a collection efficiency of 90%.

Potential Water Harvested = 621mm x 1,000 sq. ft x 0.90 = 560,700liters

Choosing the Right Tank Size:

The size of the storage tank depends on your water needs and how long you want the stored water to last during dry periods. As a rough guideline, a household of four might require a tank in the range of 5,000 to 10,000 gallons for significant water savings.

Keep in mind that it's advisable to consult with professionals like Devco Plumbing to accurately assess your specific situation. They can consider local conditions, your water usage patterns, and help you select an appropriate tank size for optimal rainwater harvesting benefits.