Out of the 38 inspected, 22 received such judgments, according to annual reports from the Social Services Inspectorate and the Audit Commission.
The English joint review team's sixth annual report said although several councils were performing well, out of the 30 inspected in the last year 'a number had disappointing outcomes'.
'The biggest challenge facing councils is to ensure they assess potential new customers in a timely and consistent manner,' the report said.
The Welsh report found people are being put at risk because of delays, while senior management is often unaware of what is going on at the front-line.
Audit Commission controller Sir Andrew Foster said: 'Overall, social services are still not where they should be, but steps are being made in the right direction.'
SSI chief Inspector Denise Platt said: 'There is excellence in many services, but it is spread too thinly. Councils should not be afraid to make change to the way they have delivered their services in the past.'