WA farmers exceeded 15 million tonnes of the grain for the first time in history this season beating a previous record set in 2003-04 of 14,695,321 million.

A truckload of wheat delivered in the Albany zone on Tuesday pushed total grain receivals in the state past 15 million tonnes.

CBH Group General Manager Operations Colin Tutt said reaching the milestone was a great achievement for all involved, particularly when the 2011-12 harvest had been a challenging one.

Despite the record haul WA Farmers Federation president Mike Norton said late rains from October through December did a lot of damage to the quality of grains.

"It affects the colour of the grain especially the barley, the seed starts to germinate, they start to sprout and that affects the starch levels in the grain," he said.

"The bread won't rise so the quality of the grain gets downgraded."

In start comparison Mr Tutt said last year's haul was only about 6.5 million, but was of a very high quality fetching top dollar for growers.

"The value of the crop has diminished considerably possibly by anything up to $100 per tonne," he said.

"If you put that over 15 million tonnes, that's a lot of money."

Mr Norton said farmers were already seeing a diminished bottom line as they added up their spreadsheets.

"Even though we've had a record crop the amount of money they get for it isn't going to ensure a windfall for them," he said.

The chief grains making up the total were wheat, barley, canola, lupins and oats.

Mr Tutt said the 2011-12 harvest was expected to continue in some areas until the final weeks of February, with another 75,000 tonnes expected to be delivered.