Common Cause of Virginia endorsed a package of proposed state legislation today that would make dramatic changes in election laws and have a significant impact on reapportionment of the General Assembly after the 1980 census.

One of the bills endorsed by the public interest lobby and sponsored by Del. Kenneth R. Pulm (D-Fairfax) would authorize an advisory commission to submit a reapportionment plan to the assembly after the census.

Reapportionment now is the sole responsibility of the legislators, who redraw their districts every 10 years in a process heavily influenced by senior incumbents who use their power to preserve safe districts for themselves.

Another bill backed by Common Cause would require the House of Delegates to create single-member districts for all of its 100 members when it reapportions in 1981.

Republicans and black politicians generally have been the strongest advocates of single-member districts. Both have seen their concentrations of voting strength overwhelmed by white and Democratic majorities in large, multi-member districts.

However, the bill requiring single-member districts is sponsored by Del. A. L. Philpott (D-Henry), the majority leader of the House and perhaps the most influential legislator in Richmond. Philpott represents a three-member district in which political survival depends on a precarious balance of political factions.

Judy Goldberg, Common Cause executive director and lobbyist in Richmond, criticized multimember districts today as devices that reduce accountability of legislators, adds, to the cost of running for office and discriminates against minority and regional interests.

A delegate from a single-member would represent about 52,000 persons after 1980, but multi-member districts now in existence include up to 300,000 residents. Fairfax County is divided into two five-member districts. Eighty of the 100 House members now are elected in multimember districts.

In the Senate, only the three members from Norfolk are elected in a multimember district. Creation of single-member districts in Norfolk probably would increase the chances of electing a black senator from that city.

In addition to the reapportionemnt measures, Common Cause also is strongly supporting a bill sponspored by Del. Vincent F. Callahan (R-Fairfax) that would provide public financing for statewide candidates.

The organization also called for a measure directing the state Board of Elections to enforce compliance with the state's campaign financial disclosure laws.

The board now receives the financial reports of candidates and political committees, but has rejected Common Cause appeals that it prosecute apparent failures to comply with disclosure requirements. Enforcement is now left to city and county prosecutors.

Common Cause also endorsed ratification of the proposed Equal Rights and District of Columbia Representation Amendments to the U.S. Constitution, application of the Freedom of Information Act to college boards of visitors, authorization of citizen lawsuits to force compliance with conflict of interest laws and transfer of some functions of the State Corporation Commission to the executive branch of the government. The SCC is the state's umbrella regulatory agency.

D.C. representation was given a single sentence at the end of the six-page Common Cause legislative statement, an indication that the organization will concentrate its energies on its election package and other bills during the Assembly session that begins Jan. 10. The D.C. amendment is given almost no chance of ratification in Virginia.

Common Cause endorsements of legislation were once regarded as at least one strike against a bill in a Virginia legislature often resentful of "reform" measures that implied the need for greater official accountability. However, the organization has had a significant impact in recent sessions, especially on campaign disclosure laws, disclosure by lobbyists and freedom of information measures.