Browse Forums General Discussion 1 Mar 11, 2019 11:48 pm I have just taken over a house from the builder. Water flow is very poor and is far below the requirements of AS/NZS 3500.1:2018 clause 3.3.2: "The minimum working pressure at the furthermost or most disadvantaged fixture or outlet shall be not less than 50 kPa (5 m head), at the flow rate specified in Table 3.2.1". for example, the garden tap (nom 15mm) at the mains entry point into the house should supply 12 litres/minute but supplies less than 4 litres/min with the 5m head. The line pressure is good at about 35m. I haven't approached the builder yet as I expect him to try and talk his way out of it … how do I convince him that it is his responsibility to get the supply up to scratch. any advice much appreciated Ted Re: low water flow 3Mar 12, 2019 10:24 am tedbain I have just taken over a house from the builder. Water flow is very poor and is far below the requirements of AS/NZS 3500.1:2018 clause 3.3.2: "The minimum working pressure at the furthermost or most disadvantaged fixture or outlet shall be not less than 50 kPa (5 m head), at the flow rate specified in Table 3.2.1". for example, the garden tap (nom 15mm) at the mains entry point into the house should supply 12 litres/minute but supplies less than 4 litres/min with the 5m head. The line pressure is good at about 35m. What State are you in? You are very well informed which is very unusual, have you had previous advice elsewhere? The "garden tap (nom. 15mm) at the mains entry point into the house" I assume is the fixture closest to the main's water meter. This is not the most disadvantaged fixture if it is. The required flow rates to each fixture also have to account for the minimum Probable Simultaneous Demand (PSD) as shown in AS/NZS 3500.1 Table 3.2. The minimum PSD demand requirement for a single dwelling is 0.48 litres per second (28.8 lpm). To find out how badly restricted any fixture is, you fully open other cold water taps that will give you the total PSD and take lpm measures. For example, you would fully open your 12 lpm tap, the laundry tub 9 lpm tap and a standard outlet 9 lpm basin tap which gives a total of 30 lpm and record each fixture's measure. Given the facts posted, you have a serious restriction in the pipe work and if the 15mm garden tap is the closest fixture, the restriction is between that tap's branch offtake and the meter. This indicated a problem with the meter given that the static pressure is good. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: low water flow 4Mar 12, 2019 11:26 am booster pump won't help - there is something hindering flow between the main and the tap just past the meter … pressure without flow is fine. I think most likely there is a length of buried pipe that is almost flattened - doesn't affect static pressure but restricts flow. Question is really how does one get the builder (or his plumber) to own the problem and get it fixed. Who or what authority will back me up. Re: low water flow 5Mar 12, 2019 11:41 am If the flow rates are not compliant, they have to fix it. It depends on your region as to how you proceed if the builder is reluctant but it is in his best interest to have the issue fixed. You have the required knowledge and understanding of the regulatory standing, just send him a polite Email. That way notification of the issue is documented. 3in1 Supadiverta. Rainwater Harvesting Best Practice using syphonic drainage. Cleaner Neater Smarter Cheaper Supa Gutter Pumper. A low cost syphonic eaves gutter overflow solution. Re: low water flow 6Mar 15, 2019 10:24 pm SaveH2O … I'm a retired civil engineer in NSW - thanks for your thoughts turned water off at meter opened 3 taps with buckets underneath, turned water on for 30 seconds, water off and measure. And problem gone - total flow gone from about 20 l/m to 51 - 40 at first garden tap, 8 at second garden tap and 3 at laundry sink - have no doubt other taps okay if 1st tap throttled back to 12 l/m. Looks like whatever was causing the problem got flushed out - wasn't looking forward to breaking into the concrete driveway. Good luck with it. I don't know what the cost of a nice bidet seat with a 25mm air gap will be but you are obviously deducting the cost of a RPZ valve and its… 9 6983 You may still have a case, but your next step is to speak to a lawyer. 3 1617 If you can calculate the reasonable charged head from let's say 100mm below the gutter to the top of where the vertical riser's horizontal discharge pipe will be, that… 11 17530 |