HHP has two completely separate autonomous rainwater systems – potable and non-potable. Since the completion of the houses in 1998, water from both systems has been tested regularly.

Our latest results (September 2011) indicate that our drinking water is perhaps cleaner than most branded bottled water!  Could it really be that our filtered rainwater can be just as clean as the commercial products that line our supermarket shelves?

Broadly speaking there are two general categories of analysis; metals and bacteriological. In our case, the former remained consistently low with the exception of aluminium. Although previous years’ test results showed zero aluminium, September 2011 sample showed levels of 0.109mg/l. This figure is acceptable within the limits for small water systems (0.2 per mg/l) but larger water treatment plants are limited to 0.1 mg/l. Whatever limit we choose, we still feel this is unaccountably high – can anyone shed any light on this contaminant?

The bacteriological analysis proved to be both interesting and reassuring. Of all these, the Total Viable Count result (TVC) was of most interest. The test estimates the total amount of living organisms in a set volume of water at two separate temperatures; 22ºC (TVC 22C) and 37ºC (TVC 37C). The samples are left at that those temperatures for a period of 2 days and 3 days respectively, allowing any organisms present to populate the sample. These tests  have been carried out on bottled waters with levels ranging between 42/ml and 32,659/ml for TVC 22C and between 3/ml to 1,950/ml for TVC 37C. Our drinking water, by comparison, showed 0/ml and 20/ml respectively. Even our aquaculture lake, which is full of fish, and receives liquid effluent from the reed bed, still manages to produce low results at TVC 22C 166/ml!

The irony is that even though we residents at Hockerton Housing Project consume approximately 2000 litres each per year of our harvested rainwater, we still have to provide paying visitors with bottled water! This is because, to comply with current health and safety guidelines, we would have to test our water on a monthly basis, currently around £1200 per year. Compare this with our visitors’ consumption of around 50 bottles of branded water per year, around £50 – the figures speak for themselves! (People on our tours also appreciate the tea, coffee and some wonderful local apple juice we supply for free!)

Date posted: January 25, 2012 | Author: | No Comments »

Categories: Rainwater Harvesting Water systems

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