Five years ago, California's voters, in angry reaction to Watergate corruption, overwhelmingly passed what was then the most comprehensive political disclosure and ethics law in the nation.

Today, that act has been copied, in whole or in part, by 38 other states, according to Thomas Houston, chairman of the state Fair Political Practices Commission. The FPPC, which was set up by the act, is one of the leading forces behind the Council on governmental Ethics, a nationwide body made up of such commissions.

But the impact of the act in California is mixed. Money, in the words made famous by California state treasurer Jess Unruh, is still the mother's milk of politics.

Although the courts have declared some provisions of the law invalid, the act has had a real impact, especially on the local level, where conflict provisions have prevented members of planning commissions and boards of supervisors from voting on matters in which they have an economic interest.

Also, the act's requirement that politicians disclose the source of all campaign contributions and who arranged for them has enabled the press and political opponents to relate contributions to votes.

However, California's 120-member legislature just finished its 1979 session and it was, for a variety of reasons, the best year for special interests since the 1974 election brought in the lawmakers who have since become known as the Watergate Babies.

There were bruising battles this year over liquor legislation, with the state's wholesalers struggling to retain exclusive distributorships against liquor retailers. Wholesalers won the struggle.

Also, California's insurance agents won a battle that included overriding a gubernatorial veto, and a humiliating defeat for Gov. Edmund G. (Jerry) Brown Jr. on a bill to keep banks from selling hundreds of millions of dollars in premiums on credit-related insurance.

Because of these special interest issues, several practices emerged this year in the legislature.

Wining and dining of lawmakers, which lobbyists were prohibited from doing by the Political Reform Act, is on the increase by the employers of lobbyists.

Before the act was passed, lawmakers and their staffs dined and drank at several downtown restaurants and simply signed the names of top lobbyists to the chits. Some lobbyists ended up with liquor and food bills running in the thousands of dollars a month.

Today, according to a study released by the FPPC, there has been a 5-fold increase in wining and dining by the lobbyists' employers, who fly into Sacramento to woo legislators.

In some isolated cases, lawmakers have taken their entire staffs to exclusive restaurants in Sacramento and sent the bills to the special interests. One lobbyist also said he and two other lobbyists were asked to host a dinner recently for 10 lawmakers. They forwarded the bills to their employers.

Also, campaign contributions are increasing enormously. In one 1978 election for an open state Senate seat the two candidates spent $1 million between them for a job that pays $26,000 annually.

The act prohibited lobbyists from making campaign contributions because they too often resembled bribes, since they were often made on the day of crucial committee hearings.

That section of the act was voided recently by the state supreme court. But its effect had been virtually nullified anyway because "legislative liaisons" or "vice president for government affairs" or other donors designated by their associations or firms would show up -- contributions in hand -- on the day of committee votes affecting their interests.

Several lawmakers are creating their own political war chests by virtually selling important votes. In one such case an assemblyman was said to have picked up $82,000 in political IOUs, donations to be made to other candidates to ensure loyalty, for two committee votes.

In one case, a segment of the financial community reportedly made $50,000 in contributions to Democratic candidates throughout the state for one vote.

The other $32,000 reportedly was picked up this year from another segment of the financial community. It is to be spent in the next election, and presumably the loyalty gained by those contributions will be a factor the next time the California Assembly elects new leadership.

Nonetheless, said Robert M. Stern, chief counsel for the FPPC, the 1974 campaign act "is a disclosure statue and we are getting disclosure. At least the disclosure provisions are giving us this information and the people will have to decide whether they want to change the facts of all this special interest money coming in."