Twelve delivered better financial results than in 2015.
Revenue across the unions was $78.2m in the 2016 financial year, up from $66.4m the year before - a rise of 17.8 per cent.
Deloitte said a main part of the result was "the substantial increase in grants" being provided by New Zealand Rugby.
"It is expected that the increased grants, to be used to invest in the development of the game at the grassroots, will continue in the foreseeable future," Deloitte said.
Deloitte partner Grant Jarrold said the unions made big improvements.
"The positive takeaway is that the largest increase in expenditure, in percentage and dollar terms, was in the 'growing the game' category," said Jarrold.
"This reflects that increases in revenue was reinvested back into grassroots rugby. Spending on this category increased by $2.9 million, the largest year-on-year increase since we began doing this annual review," he said.
"However, the unions still need to remain vigilant with their spending. After all, they are the current caretakers of the game and with that comes the responsibility to ensure that funds are spent purposefully, and are aligned to the strategy of growing the game in the community," he said.