Spillable Water Accounts Explained: How Victorian Carryover Risk Actually Works

Why spillable accounts exist

Victorian carryover lets you hold unused allocation across the 30 June boundary — up to 100% of your water share volume. But that water has to physically sit somewhere: in Eildon, Hume or Dartmouth, occupying storage capacity through winter and spring.

That creates a problem. If everyone's carried water occupied "guaranteed" airspace in the dam and a wet winter filled the storage, the system would have to spill water that belonged to someone. The spillable water account is how Victoria allocates that risk: carried water is held on the explicit condition that if the dam spills, carryover takes the loss first.

It is the price of the most generous carryover scheme in the Basin. NSW has no spill mechanism but caps carryover instead (50% of entitlement in the NSW Murray, with a 110% account limit); SA caps carryover near 20%. Victoria gives you 100% — with strings attached.

How the mechanism works

On 1 July, your carried-over allocation is credited to a spillable water account linked to your allocation bank account. From that moment two rules apply:

1. You cannot use or trade it yet. Water in the spillable account is frozen — not available to irrigate with, not available to sell — until the resource manager declares a Low Risk of Spill for your system.

2. It can be forfeited. If the storage fills and spills before that declaration, the spill is deducted from spillable accounts proportionally across all holders in the system. If the system spills 10% of total spillable water, every holder loses 10% of their spillable balance. You cannot jump the queue, and holding a small volume does not protect you — the haircut is pro rata.

New-season allocation announced from 1 July onwards is never spillable. The mechanism only ever applies to carried water.

The LROS declaration

The Low Risk of Spill (LROS) declaration is made by the storage manager — the NVRM in northern Victoria — not by entitlement holders. Through winter and spring, the manager monitors storage levels and inflow forecasts. When the probability of the storage filling drops below the risk threshold, LROS is declared and spillable water transfers into your ordinary allocation account: fully usable, fully tradeable, spill risk over for the year.

The timing is everything:

• Dry years: LROS can be declared early — sometimes within weeks of 1 July — because a low storage obviously is not going to fill. Your carried water is usable almost immediately.
• Average years: Declaration typically lands somewhere in spring.
• Wet years: Declaration comes late or never. In the 2021-2023 La Nina sequence, Eildon hit capacity and spillable accounts took real losses. Holders watched water they had paid for evaporate from their balance — exactly the scenario the mechanism is designed to put on carryover holders rather than the system.

Note the asymmetry: the years when carried water is most valuable (dry years) are the years when the spillable constraint bites least. The years when it bites hardest (wet years) are when carried water was worth the least anyway. The mechanism punishes carrying into wet years twice — low prices and spill losses. This is why we tell clients the carryover decision is really a storage-and-outlook decision, not a habit.

Goulburn vs Murray spill risk

Where your carryover is deemed held matters. Zone 1A carryover sits against Eildon (3,334 GL). Zone 6 and 7 carryover is deemed held in the Murray storages — Hume and Dartmouth, 6,861 GL combined. The larger Murray buffer fills less often, so Murray-system carryover has historically faced fewer spill events than Goulburn carryover. If you hold entitlement in both systems and have a choice about where to park surplus, the Murray side offers slightly better protection in wet sequences.

What this means in June 2026

With Eildon in the mid-40s and a dry outlook, the spillable mechanism is close to a non-issue for WY2026/27 carryover: spill probability is negligible and LROS is likely to be declared early in the season. The practical risk this year is not spill — it is over-carrying past your 100% cap, which forfeits the excess at 30 June regardless of conditions. Run the numbers in our end of water year checklist.

In a future wet year, re-read this article before you carry. The mechanism has not changed; the conditions will have.

Frequently asked questions

Can I sell water that is in my spillable account?

Not while it is spillable. It becomes tradeable when the storage manager declares Low Risk of Spill and the water moves to your ordinary allocation account. If you need to sell early in the season, water still locked in a spillable account cannot help you.

How do I know when LROS has been declared?

The NVRM publishes declarations for each system, and the Victorian Water Register reflects the change in your account. Your broker will also know. In dry years expect it early; in wet years watch storage trajectories — a storage tracking toward capacity means a late declaration and live spill risk.

Is new allocation ever spillable?

No. Only carried-over water enters the spillable account. Allocation announced through the season's determinations goes straight to your ordinary account and is immediately usable and tradeable.

If the dam spills, do I lose everything?

You lose proportionally. Forfeiture is applied pro rata across all spillable balances in the system, matched to the volume actually spilled. Partial spills mean partial losses — but in a major flood year, losses can approach the full balance.

Does carryover parking avoid spill risk?

No. Parked carryover is still spillable water — parking solves a cap problem (you have more water than your entitlement volume can carry), not the spill exposure. The spill risk assessment is identical whether the water sits on your entitlement or someone else's.