Work out roughly how much tank you need for your block, and how much of your yearly demand a roof that size can actually cover. Built for acreage properties around Maudsland, Nerang, Advancetown and the Numinbah Valley.
Indicative only. Sizing assumes 85% collection efficiency after losses and first-flush diversion, and a 60-day dry-spell reserve. Local council rules, BASIX-equivalent requirements and bushfire service-water obligations can all change the answer — we check those on site before anyone orders a tank.
The five things people get wrong on their first tank. Written from what we find on call-outs, not from a manufacturer's brochure.
Only the roof planes actually guttered into the tank collect anything. A 320 m² house with one side plumbed is a 160 m² catchment, and the tank that was sized on the bigger number spends most of the year half empty and gets blamed for it.
The first wash off a roof carries the dust, leaf litter and bird mess that accumulated since the last fall. A diverter sized at roughly 20 litres per 100 m² of catchment sends that away from the tank. It is the cheapest part of the system and the one most often left off.
A pump has to deliver flow at the head your block demands, which on a sloped hinterland site means the vertical rise from tank to the furthest outlet plus friction along the run. Two outlets open at once is the case to size for, not one.
Most inline drippers are rated around 100–300 kPa. Feed them straight off a pressure pump and emitters blow off the line or the flow rate stops being uniform down the run. A pressure reducer and a filter ahead of the zone solves it permanently.
A poly tank arrives on a tilt tray and needs a path in. We have re-sited more than one order because the only approach was through a garden bed the owner had just finished. Work out the access before the pad goes down.
Measure the catchment, check fall and pad location, confirm council and bushfire requirements, and put a sizing and pump recommendation in writing before anything is ordered.
Poly and steel-lined tanks from 2,000 to 50,000 litres, pad prep, downpipe and gutter connection, first-flush and leaf diversion, overflow to legal discharge.
Pump selection sized on head and flow, pressure vessels, automatic town-water changeover, and covers for the ones that live outdoors in the sun.
Zoned drip line for gardens and orchards, filtration and pressure regulation, solenoid valves and controller setup, and seasonal scheduling that suits what is actually planted.
Pump faults, leaking fittings, blocked filters, controller reprogramming, and tank cleaning on systems that have been left a few years too long.
We are a small water and irrigation outfit working the acreage blocks behind the Gold Coast — Maudsland, Nerang, Advancetown, Wongawallan and up through the Numinbah Valley. Most of what we do is unglamorous: sizing a tank properly the first time, picking a pump that will not be replaced in three years, and putting drip line where the plants are rather than where the trench was easy.
The calculator above is the same arithmetic we run on a site visit. It is on the site because people kept asking for the number over the phone, and a rough figure they can check themselves is more use to them than a quote they cannot compare.
We do not sell tanks online and we do not quote sight-unseen. If you want a number for a block, email us the address and roughly what the tank is for, and we will tell you what it needs.