Fire Order, hydrants, water flow, and policy issues

It’s not a State Government policy issue, but rather is symptomatic of what happens when pressure (sorry) from developers forces Utilities such as Sydney Water to supply its services to multi-unit developments that tower above allotments where a few single dwellings once stood.

Electricity supply utilities can require these developers to provide for sub-stations within their developments and Councils require stormwater detention systems, but Utilities providing gas, water, and sewerage services are largely constrained by the limitations of their in-ground infrastructure.

As an aside but for the very same reasons, the peak dry-weather flows in Greater Sydney’s sewerage system were nearing design system capacities 12 years ago, and that design is four (4) times the expected maximum – so expect those problems to surface some time soon.

Anyway, back to your immediate problems. Sydney Water’s Operating License permits it to supply its services at levels below those given in its Standards of Service provided it negotiates a Service Agreement with affected customers.

That Service Agreement should give you and other residents some recourse, and may even secure some assistance with overcoming the issues that you’ve mentioned in your post, including some medium term forecasts.

Your Owners Corporation could act as the conduit (sorry again) to initiate discussions on that Service Agreement, so I’d suggest having a representative contact Sydney Water to get things moving.

There is a relationship between flow volume (kL) and pressure (kPa), but like a lot of things in the universe, that relationship “depends”(that’s a technical term ).

Using your Plan’s water supply system as an example, a pressure equivalent to say 15m head (the usual standard) at the inlet to your water supply meter does relate to the flow that emerges from that meter’s outlet BUT the design of your internal water reticulation system builds-in “friction losses” that both increases the flow velocity and decreases the pressure.  

If you look at your Plan’s 40 year-old internal water reticulation system as a giant garden hose, and its numerous elbows, bends, tees, taps, irregular pipe sizes, and posibly corrosion affected sections as a nozzle at the end of that hose, then a partial closure of that nozzle creates a friction loss resulting in a high pressure / high velocity flow, and when that nozzle is fully opened you’ll get a higher flow volume (L) but at less pressure.

I suspect that’s a simile of the problem at your Plan, as like most reticulation systems in older multi-unit developments (and some new ones), yours was not designed and has probably “grown” over the years through the incorporation of 40 years worth of ad-hoc additions, including all those friction loss-creating bits and pieces that together contribute significantly to the problem outlined in your posts, perhaps aided and abetted by a Sydney Water supply system that’s providing pressure right on the acceptable limits.

Whilst I don’t know the nature of the services that your Plan has to date procured, its challenge is to find a Hydraulic Engineer, as opposed to a plumbing consultant, who may well be able to recommend the implementation of some cost-effective design changes to your Plan’s internal water reticulation system. I’d very strongly recommend doing that in conjunction with Sydney Water, that by the way is a Corporatised Trading Enterprise and not subject to State Government interventions to its core business activities, apart from the (at least) annual raid on its coffers under the guise of a “shareholder dividend”.

Please understand that whilst I do appreciate your feed-back, I’m trying to point out that lobbying the Council to pressure Sydney Water will in my opinion be far less effective than your O/C engaging a professional to, together with Sydney Water, examine your Plan’s own internal water reticulation system  holistically with that operated by Sydney Water.