The Environmental Protection Agency is about to issue proposed revisions to its water quality standards that would make it easier for state and federal water control officials to downgrade water quality goals and could, in some cases, reduce public participation in official decisions to reduce existing water quality levels.

Many EPA officials say they believe the proposed changes would make the water quality regulations more flexible and realistic, encouraging increased compliance by state officials who may have felt the existing rules were unnecessarily rigid and failed to accommodate differing regional situations.

The draft of the rules, "approved in principle" by EPA Administrator Anne M. Gorsuch earlier this week, would not permit the quality of streams, rivers or lakes to be degraded if it would change their current use.

"Existing uses must be maintained," said Steven Schatzow, director of EPA's Office of Water Regulations and Standards.

However, according to an EPA official who asked not to be identified, at the Office of Management and Budget's insistence the proposed regulations also ask for public comment on several other options.

These include allowing "changes in existing uses if maintaining that use would effectively prevent any future growth in the community or if the benefits of maintaining the use do not bear a reasonable relationship to its costs."

The issue of water quality regulations has been one of the most politically sensitive to confront the EPA in the Reagan administration.

The EPA's legislative proposals to change a separate set of water quality regulations, which govern cleanup technology to be used by industrial polluters, created new strong opposition.

Daniel Weiss, conservation associate of the Izaak Walton League, said yesterday that the proposed regulations are "a signal to the states--it would allow them to downgrade water quality more easily and, if they still have dirty water, they can keep it that way."

Standards addressed in the current proposals govern plans that states have promulgated, originally under the Clean Water Act of 1965 and later under more stringent laws passed in 1972, setting goals for how clean their lakes, rivers and streams should be and establishing how clean their water is now.

The 1972 act and 1975 regulations implementing it required that waters be made safe for fishing and swimming, if possible.

Under existing regulations, the goals for a stream's water quality could not be less than the fishing-swimming standard unless EPA-mandated pollution control technology was insufficient to meet the goal and the cost of additional technology would result in "substantial and widespread economic harm," Schatzow said.

The new proposals would relax that standard, giving states more flexibility to weigh the benefit of optimum water quality goals against costs of achieving them.

"Suppose a stream that was proposed to be cleaned up enough to support a bass fishery only has carp, because the dissolved oxygen level is too low," Schatzow said.

"But in order to get enough dissolved oxygen to support bass, we're going to have to put on very advanced treatment technology and raise the sewer users' monthly bills from $6 to $20 or $40.

"Under the draft regs, states are allowed to do an analysis and make a judgment saying we don't think it's worth it. The value of going from a carp stream to a bass fishery is not worth quadrupling the sewer charges. The proposed reg allows the state to go through a public process and justify the decision."

In some cases, he added, existing conditions -- dams that prevent fish going upriver to spawn or the shallowness of the stream in question -- effectively may preclude the goal of having certain kinds of fish in the stream.