Perth’s dams are 40.0% full (246.9 GL of 616.9 GL), up 0.1 points in a week; a year ago the same 10 storages were 46.2% full.
11 storages reporting to the Bureau of Meteorology, latest reading 2026-09-26 02:00. Refreshed every 30 minutes.
The table holds the eleven Water Corporation storages the Bureau of Meteorology counts as Perth’s supply, from Mundaring Weir in the hills east of the city to Stirling and Samson Brook dams out near Harvey, each with its latest volume, percentage and weekly movement. Below it are how Water Corporation builds its own metro total, why desalinated seawater now passes through these reservoirs, and why anglers have to look further south for a dam they can fish.
Percentage full is the Bureau’s accessible volume divided by the accessible capacity, as on its storage dashboard, so it can differ by a point or two from the operator’s daily report, which is the official figure. Year ago is the same storage on the same date last year. Dams with a fishing page link to it.
| Storage | Full | Volume (ML) | Capacity (ML) | 7 days | Year ago | Updated | Fishing |
|---|---|---|---|---|---|---|---|
| Serpentine DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 32.5% | 44,401 | 136,660 | +0.1 pts | 33.6% | 26 Sept | No public fishing |
| South Dandalup DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 9.4% | 11,801 | 125,060 | −0.1 pts | 10.4% | 26 Sept | No public fishing |
| Canning DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 63.3% | 57,178 | 90,290 | −0.7 pts | 70.1% | 26 Sept | No public fishing |
| North Dandalup DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 58.0% | 42,835 | 73,830 | −0.4 pts | 69.5% | 26 Sept | No public fishing |
| Mundaring WeirPerth and the Integrated Water Supply Scheme (Water Corporation) | 36.6% | 21,017 | 57,420 | +0.1 pts | 51.5% | 26 Sept | No public fishing |
| Wungong DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 47.3% | 26,669 | 56,370 | +2.2 pts | 55.0% | 26 Sept | No public fishing |
| Stirling DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 50.8% | 28,236 | 55,600 | — | 62.7% | 21 Sept | No public fishing |
| Victoria DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 78.0% | 7,345 | 9,413 | −0.9 pts | 85.1% | 26 Sept | No public fishing |
| Samson Brook DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 59.5% | 4,701 | 7,899 | +0.9 pts | 75.2% | 23 Sept | No public fishing |
| Churchman Brook DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 46.5% | 1,023 | 2,200 | +0.5 pts | 60.7% | 26 Sept | No public fishing |
| Serpentine Pipehead DamPerth and the Integrated Water Supply Scheme (Water Corporation) | 77.3% | 1,670 | 2,160 | +5.4 pts | — | 26 Sept | No public fishing |
Among storages of 5 GL or more.
90% and over60–90%30–60%under 30%no capacity published
Combined accessible volume of the 11 storages with a published capacity, as a percentage of their combined capacity, one value a day.
The Bureau lists eleven Water Corporation storages under Perth: Canning, Churchman Brook, Mundaring, North Dandalup, Samson Brook, Serpentine, Serpentine Pipehead, South Dandalup, Stirling, Victoria and Wungong. Water Corporation’s metro total on its dam levels page draws on thirteen. It adds Conjurunup Pipe Head and Lower Helena Pumpback, two small storages that do not appear in the Bureau’s list, and it calls two of the shared dams by slightly different names, Serpentine Main and Samson. Stirling Dam on the Harvey River and Samson Brook Dam lie well south of the other hills dams, and Water Corporation notes that its historical total dam volumes changed when those two were added to the metro figure. Not all of their water is counted as Perth’s: the Bureau’s note on Water Corporation data explains that the corporation runs an account-type system to decide how much of the water in Stirling and Samson Brook belongs to Perth, while the Bureau can only apply fixed shares, 66 per cent of Stirling and 75 per cent of Samson Brook. That alone produces small differences between a Perth total from the Bureau and the one Water Corporation publishes.
Water Corporation works out the volume in each dam by combining a water level reading with a model of the ground beneath the surface. The level comes from a float-well device or a submerged pressure sensor, both calibrated against gauge boards at the dam, and the corporation puts the uncertainty in a level at typically one to two centimetres. On reservoirs with a large surface area that small error becomes a large one in volume, and across all the hills dams it adds up to about 0.4 to 0.5 gigalitres, which is why metro totals are shown to one decimal place. Its larger dams carry a device that measures volume every day, while smaller dams have a measurement graph painted on the wall that staff read in person each week. The dam levels page, which also shows rainfall and water use, is refreshed every working day, and each dam’s own page sets its current volume against the same date a year earlier, with a fourteen-day table and a year-by-year chart of monthly averages. Streamflow is handled separately: it is estimated every Thursday morning with a water balance model built in the 1980s and revised in 2012, and the corporation treats Thursday’s figure as settled only after 5 pm.
The rows and the total on this page use the Bureau’s basis, the same one its dashboard uses for every state: accessible volume divided by accessible capacity, where accessible means the water above each dam’s lowest outlet. Water Corporation divides gross volume by gross capacity, dead storage included; the Bureau’s supplier note confirms that the corporation’s volumes include dead storage, and adds that the two estimate daily values in slightly different ways. Our total also adds the eleven rows in full, Stirling and Samson Brook included, and leaves out the two small storages the Bureau does not list. The result usually sits a few points below the corporation’s metro headline, and the gap is not spread evenly. At South Dandalup the Bureau puts 12,940 of the dam’s 138,000 megalitres below the lowest outlet, about a tenth of its capacity, so when the lake is low its row can read far below the corporation’s figure. Mundaring, with 63,600 megalitres in total and 57,420 accessible, and Wungong, with 59,800 and 56,370, show smaller versions of the same effect. North Dandalup differs for another reason: by our arithmetic, the volume and percentage on Water Corporation’s page imply a full capacity of about 61 gigalitres, while the Bureau counts 73,830 megalitres accessible and 74,850 in total, so the two percentages part even though the volumes agree. Timing matters too, since the Bureau’s readings for a storage can trail the corporation’s by a few days. For an official statement on Perth’s supply the corporation’s page is the reference; for comparing Perth with other cities on one basis, the Bureau’s figures are the ones to use.
In 2024–25, according to Water Corporation, desalination supplied 38 per cent of the water in the Integrated Water Supply Scheme, groundwater 34 per cent, dams 22 per cent and groundwater replenishment 6 per cent. The corporation’s history of Perth’s sources puts the dam share at 88 per cent in the 1960s and 65 per cent by the 1980s. Water Corporation built its first desalination plant in 2006 and a second in 2011; the two, at Kwinana and Binningup, can supply around half of the local need, and a plant under construction at Alkimos is planned to add up to 50 billion litres a year in its first stage. Because rain alone no longer fills them, the hills dams act more as tanks than as catchments. Water Corporation’s dam pages describe desalinated water and groundwater being stored in them during periods of low demand so that it is on hand for the hot months, and say that dam levels now rise and fall independently of rainfall; its scheme page qualifies this for groundwater, which is generally treated and sent to customers or to service reservoirs rather than into the dams. A reading that climbs in a dry month is therefore not necessarily a sign of rain in the catchment.
Water Corporation says streamflow into its dams was far more reliable before the mid-1970s, when Perth and the South West had steadier rain through autumn and spring, and averaged around 420 billion litres a year. A fall of 15 to 20 per cent in annual rainfall has since cut streamflow by about 80 per cent, because the catchments have to be soaked before any water runs off into a reservoir, and the corporation cites a projected fall of around 15 per cent in winter and spring rainfall by 2030. Its streamflow page reports monthly inflows for every dam in the Integrated Water Supply Scheme, Stirling and Samson Brook included. That scheme reaches well beyond the city: it serves over two million people across Perth, the Peel region, the Goldfields and Agricultural Region, parts of the South West and the Upper Great Southern, and in 2024–25 it sourced 337 billion litres through 15 storage dams, six groundwater treatment plants, a groundwater replenishment plant and two desalination plants. Mundaring Weir is the historic link inland, and the No 1 Pump Station beside it, now managed by the National Trust of Western Australia, tells the story of pumping water nearly 600 kilometres from the weir to the Goldfields.
Perth’s supply dams are drinking water sources, and the state’s Department of Water and Environmental Regulation protects the catchments of such sources as public drinking water source areas, divided into priority areas; Priority 1 land is generally government-owned, such as state forest, and there the aim is to avoid any unnecessary risk to water quality. Its recreation policy, Operational Policy 13 of June 2019, treats fishing, marroning, boating and swimming as incompatible both in reservoir protection zones, which normally reach two kilometres back from a reservoir’s high-water level, and in the outer surface-water catchments, and around Perth’s reservoirs public access to those zones is prohibited except along public roads. DPIRD’s south-west freshwater guide is blunt about it: drinking water supply dams managed by Water Corporation are closed to fishing, and its marron guide adds that penalties apply in those dams and their catchments. The visitor pages say the same dam by dam: no fishing, marroning or contact with the water at Mundaring Weir, no fishing or kayaking at North Dandalup, and an exclusion zone around Victoria Dam and the streams feeding it. The hills dams are still worth a visit for picnics, lookouts and walk trails, although Canning Dam is closed for maintenance from October 2026 to February 2027 and the South Dandalup picnic area shut permanently at the end of January 2026. For a line in the water, the licensed trout and marron dams south of Perth, Harvey, Logue Brook, Waroona and Wellington among them, are covered on our WA dam levels page.
The table gives the latest Bureau of Meteorology volume and percentage for each of the eleven Perth storages, with the change over seven days. Water Corporation publishes its own metro total every working day, calculated from gross volumes, dead storage included, so the two usually differ by a few points.
Water Corporation’s metro total covers Canning, Churchman Brook, Conjurunup Pipe Head, Lower Helena Pumpback, Mundaring, North Dandalup, Samson, Serpentine Main, Serpentine Pipehead, South Dandalup, Stirling, Victoria and Wungong. The Bureau publishes eleven of them, leaving out the Conjurunup and Lower Helena storages.
Water Corporation links it to a drying climate: annual rainfall is down 15 to 20 per cent and streamflow into the dams by about 80 per cent since the mid-1970s. The dams are now used mainly to store water from other sources, so their level follows demand and transfers as much as rain.
About a fifth. For 2024–25 Water Corporation gives dams 22 per cent of the Integrated Water Supply Scheme, against 38 per cent from desalination, 34 per cent from groundwater and 6 per cent from groundwater replenishment.
No. DPIRD lists Water Corporation’s drinking water supply dams as closed to fishing, and the corporation’s visitor pages rule out swimming and other contact with the water at dams such as Mundaring and North Dandalup. Licensed trout and marron fishing is allowed at South West dams such as Harvey, Logue Brook, Waroona and Wellington.
Data: Bureau of Meteorology, Water Data Online and the Australian Water Storages dataset, © Commonwealth of Australia, CC BY; volumes supplied by © Water Corporation. Where the Bureau lists no capacity, or its capacity and volume are on different bases, a row shows the volume only. Text by Pablo Ruiz Quintero.
The facts on this page were checked against these pages, from the agencies, park services and operators that manage the water on 28 September 2026; anything we could not verify was taken out. Written by Pablo Ruiz Quintero. Errors are published in the verification log.