As many as 30% of all planning applications now involve the historic environment in some way, EH claims.
With each conservation officer managing an average of 700 listed buildings and 16 conservation areas the survey claims that workloads are often impossible.
In response to the survey, EH, with the Office of the Deputy Prime Minister and the Department for Culture, Media and Sport, is urging each local authority to appoint a councillor or senior officer who can champion historic buildings.
EH will contribute what chief executive Simon Thurley called a "significant investment in partnership training to raise professional standards that will enable local authorities to deliver a more prompt, fair and consistent service to clients".
EH is also encouraging local authorities to channel part of the ODPM's £350m grant for boosting planning departments into providing additional conservation resources.