Queensland's second largest dam, Fairbairn Dam near Emerald, has received almost half a Sydney Harbour's worth of water in a week.
Since last Tuesday, more than 200,000ML have flowed into the dam and its capacity has risen from 20.6 per cent to 36.7pc or 478,000ML.
Sydney Harbour holds about 500,000ML.
It's the highest Fairbairn Dam levels have been in almost five years, last reaching more than 36 per cent in November 2017.
The dam may continue to receive minor inflows over the coming days.
On the back of the welcome news, dam operator Sunwater says it will review announced allocations for the Nogoa Mackenzie Water Supply Scheme once inflows into the dam cease.
"Due to the region's dry conditions in recent years, medium priority customers in the scheme have started three of the four previous water years at zero per cent announced allocation," a company spokesperson said.
"An allocation increase will be welcome this early in the water year."
Several of the region's cotton growers have already planted, but with more rain forecasted and allocations likely to rise from the current 4pc, more cotton is expected to go into the ground before Christmas.
Central Highlands Cotton Growers and Irrigators Association Inc executive member Aaron Kiely said it was a relief after years of drought.
"The last five years have been very dry and each year we have taken the opportunity [to plant] when it has rained, and then the allocation has increased, but this year it's looking a little more promising," Mr Kiely said.
"With the rain right now at the end of October and inflow into the dam, it's a good opportunity to plant cotton."
Mr Kiely said growers could expect to hear about changes in allocation soon, with announcements usually within 14 days of when the inflow stopped.
The Emerald grower planted about 250 hectares of cotton six weeks ago and with the rain they've just received, they'll look at planting another 200ha.
"We'll just see with the allocation going forward, but with the wet season ahead, I think [the water we have] will get us a little way through the season.
"There's more rain ahead in the next week as well, so it'll be a matter of trying to get into the ground before it gets too wet. We can plant through to the end of December, but optimally it'd be till the end of November."
He said cotton prices had dropped to $610/bale, but there was still money to be made.
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