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. In the larger Murray, Goulburn and Campaspe systems you can also hold more than your entitlement volume in the new season when dam space is available. That extra water has to sit somewhere: in Eildon, Hume or Dartmouth, occupying storage capacity through winter and spring.

That creates a problem. If water above entitlement volume 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: water stored above 100% of your water share volume is held on the explicit condition that if the dam spills, that surplus 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's private carryover is conditional and tighter. Victoria gives you room above entitlement — with strings attached.

How the mechanism works

Spillable water accounts apply in the regulated Murray, Goulburn and Campaspe systems (and for some bulk/environmental entitlements elsewhere). They do not apply in the same way in Broken, Loddon, Bullarook or Werribee — those systems use a simpler 100% rule that limits carryover plus new allocation to your entitlement volume.

In Murray / Goulburn / Campaspe, the Victorian Water Register records as spillable any carryover or new allocation stored above 100% of your water share volume. Water up to your full entitlement volume remains available in your ordinary allocation account. Two rules then apply to the spillable balance:

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 can be spillable. Once your account reaches 100% of your water share volume, further seasonal determination increases are recorded as spillable until LROS is declared.

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. Surplus above entitlement becomes usable quickly.
• 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 surplus holders rather than the system.

Note the asymmetry: the years when carried surplus is most valuable (dry years) are the years when the spillable constraint bites least. The years when it bites hardest (wet years) are when surplus water was worth the least anyway. The mechanism punishes carrying deep 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 surplus is deemed held matters. Zone 1A positions sit against Eildon (3,334 GL). Zone 6 and Zone 7 positions are deemed held in the Murray storages — Hume and Dartmouth, 6,861 GL combined. The larger Murray buffer fills less often, so Murray-system spillable balances have historically faced fewer spill events than Goulburn. 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 for WY2026/27

Water carried across 30 June 2026 entered the new season under these rules. Volumes within entitlement are available; any balance above 100% of water share volume sits as spillable until LROS. Eildon entered WY2026/27 in the mid-40s; a wet June–July then lifted storages (MDBA late July near 51%), so near-term spill risk remains low — but still watch LROS declarations if spring stays wet. The cap decision, by contrast, has already been made — anything above the 100% carry-in limit was forfeited at 30 June, regardless of conditions. For next season, plan the cap position well before year end (carryover parking can hold surplus above the cap) and 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. Water already within your entitlement volume (not spillable) remains tradeable as normal.

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?

Yes. In Murray, Goulburn and Campaspe systems, once your account reaches 100% of your water share volume, further allocation increases are recorded as spillable until LROS is declared. Allocation that keeps you at or below entitlement volume goes straight to your available balance.

If the dam spills, do I lose everything?

You lose proportionally from the spillable balance only. Forfeiture is applied pro rata across all spillable balances in the system, matched to the volume actually spilled. Water within your entitlement volume is not the first to go — that is the point of the mechanism. Partial spills mean partial losses — but in a major flood year, losses can approach the full spillable balance.

Does carryover parking avoid spill risk?

No. Parked carryover that sits above the host entitlement's volume 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 surplus sits on your entitlement or someone else's.