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South Africa is facing a new reality. Major urban centres are under growing distress caused by failing water infrastructure. Two of our biggest water boards – Rand Water and Umgeni Water – are both intimately connected with this failure.
Both are world-class institutions, but neither function alone, and all are part of a complex supply chain that is failing. Both are facing insolvency challenges because of non-payment by municipalities. All major players are trying to shift the blame, and the new normal is a last-ditch attempt by the national government to intervene through a process they call ‘water shifting’.
What does this all mean?
For starters, we need to establish a sound baseline against which we can develop our own strategies. That baseline needs to accurately measure current performance within the sectional title scheme or estate. I have been doing this since January 2023 by accurately taking a daily pressure reading of the incoming mains that feed into our estate from the Ugu District Municipality. This provides baseline data from which decisions can be taken. The data shows wild swings in water pressure over time. I define Minimum Functional Pressure (MFP) at 2.5 bar, because this is what is required to perform two critical tasks – operate electrical appliances like washing machines and provide the most rudimentary form of fire protection. Real fire protection is defined by SANS 10400, which requires a pressure of 300kPa (3 bar) with a flow of 1,200l/min per hydrant, so the MFP I use is below that defined by the state.
From this data I can show that for 18% of the time, the water service provider has met this minimum standard. Over a nine-month period, the SANS 10400 minimum of 3 bar was provided for only 11 days, with the rest of the time the pressure swinging wildly within a range of 0.2 bar to 2.2 bar. While this sobering data is for the Ugu District Municipality, the general trend is probably indicative of the entire South Coast.
So, what needs to be done by developers and owners in estates?
- The first step is to develop your own record, for without it you are simply flying blind. An integrated metering system is a true asset to have. Locate the pressure gauge at the mains feed into the estate and take daily readings. If there is no pressure gauge, then install one because this small investment will yield big dividends. Real-time data will show hourly pressure fluctuations not visible in a daily reading. Be prepared for a surprise. With this accurate record, decision-making can be better informed by facts rather than assumptions.
- The next step is to do a fire risk assessment. This has major financial implications, so it must be done thoroughly. Determine the extent to which the SANS 10400 requirement is being met. Prepare for a shock. This information will have to be processed by the trustees or directors, as well as the managing agent, because insurance cover will depend on it. This is a serious matter because insurance might not pay out if they know that SANS 10400 standards are not being met.
- The third step is to develop a water security strategy, based on the empirical data. Once it can be accurately shown the extent to which the state is unable to meet its legal obligations to the citizens, a strategy can be developed. If it can be shown that the state is consistently failing to meet the basic human needs of the residents, then self-help becomes justified on humanitarian grounds. Self-help is what will increasingly be relied on as systemic failure accelerates, so it is important to anticipate what push-back might arise from the state.
- The fourth step is to determine from the data the actual number of days that zero pressure is delivered. In the case of Ugu, there were 42 days of no flow over a nine-month period, which tells us that the actual problem is a loss of pressure rather than a loss of flow. This is important information when designing a response. How accurately we diagnose the problem determines the appropriateness (and cost) of the solution. Of those 42 days of no-flow, the longest continuous period was 11 days. This tells us that if we calculate our average water use per residential unit, and multiply that by 11 days, then we arrive at an accurate size for on-site storage. In the case of my own small estate, we store 40,000 litres, which gives us a week’s supply under a zero-flow situation.
- The fifth step is to develop the system design. Plan on a 10-day no-flow situation. Even with a 0.2 bar pressure, water is still available, so tanks can be topped up constantly during off-peak periods of demand. The central element of the design is the pressure booster pump, feeding off the tank farm. In most cases this will be sufficient, provided that the calculations are accurate. With 10 days of storage, there is sufficient buffer capacity to manage most real-life situations encountered. With so much storage, the management of Legionella becomes important, so constant circulation of water over a UV module prevents the thermal stratification needed for the potentially fatal pathogen to thrive. In our estate, we circulate the total backup water once daily, which means that theoretically each unit of water held in reserve storage will be UV treated at least 10 times before final use.
- The final step is to determine if a borehole is needed. Coastal aquifers can be tricky to manage, because of the risk of saline intrusion. In the case of our own estate, we found strong borehole water at 30 metres below sea level, over a kilometre inland from the beach. This is reliable water that falls within the SANS 241 parameters, but approaches the lower limit of the pH range and the upper limit for manganese. The water tastes good, but is aggressive in terms of corrosion, so it must be treated if it is to become a permanent supply. The lowest-cost solution to this problem is to blend the borehole water with the incoming municipal water. This is possible because of the circulating pumps needed as a mitigation measure against Legionella. A more complex solution is to dose the borehole water with food-grade caustic lye (Sodium Hydroxide NaOH). This adjusts the pH to neutral, while also precipitating out the metals such as manganese and iron typical in coastal aquifers.
In conclusion, facts are our best friends, so develop your own database of daily pressure and historic patterns of consumption. Integrated metering systems are a great benefit in this regard. The data will inform your solution, which in most cases will be centered on pressure boosting and on-site storage of at east 10 days’ supply of municipal water. The cost-effectiveness of this solution is optimal at the level of the estate, rather than at the level of the household. In most cases boreholes will not be needed, but where available, they give an estate the ability to survive the most severe disruption to municipal supply. The reliability of municipal supply can no longer be taken for granted, but the solution proposed here will give the owners peace of mind and will protect the investment into the estate.
Pressure data from the Ugu District Municipality shows that pressure fluctuates wildly, with periods of zero flow and rare occasions when SANS 10400 fire standards are met.