SAN DIEGO -- Stay out of the surf, surfers were warned Saturday.

The County of San Diego today advised swimmers, surfers and other ocean-goers of increased bacteria levels in coastal waters due to recent rainfall.

Activities such as swimming, surfing and diving should be avoided in coastal waters, including all coastal beaches, Mission Bay and San Diego Bay, for 72 hours following rain, the advisory stated.

The advisory stated levels of bacteria can significantly rise in ocean and bay waters, especially near storm drains, rivers, creeks and lagoon outlets that discharge urban runoff. The elevated levels of bacteria can persist after a rainstorm depending on the intensity of the storm, volume of runoff and ocean and current conditions.

The runoff can contain a large amount of bacteria from a variety of sources such as animal waste, soil and decomposing vegetation, the advisory stated.