The money is on top of £58m already allocated for 2014-15 to a sector which covers more than 230,000 homes.
The new money should mean a further 70-90 houses become available for renting across Wales.
The extra cash for each county ranges from just over £700,000 in Cardiff to nearly £111,000 for Merthyr Tydfil.
Finance Minister Jane Hutt said it would make "a real difference" to people's lives and also act as "an economic stimulus" for growth and jobs.
The push to build more homes for rent in the social housing sector is getting another £5.8m in Welsh government cash.