With the Nov. 8 election nearly five months past, the D. C. Board of Elections and Ethics has finally certified the last of 21 persons who won seats on the city's Advisory Neighborhood Commissions.

But that doesn't mean Washingtonians have heard the last of the matter.

The Board of Elections and Ethics is now in the process of filling eight ANC seats vacated by people who resigned or moved out of their districts. And it is preparing to advertise 26 more seats as vacant - seats for which there were no valid votes cast in the election.

ANCs are Washington's experiment in grass-roots government, introduced in 1975 when the Home Rule Charter went into effect. There are 36 ANCs throughout the city, with a total of 367 seats. Citizens who are elected to the seats are charged with advising city officials on projects and policies that effect their neighborhoods.

Those elected normally serve for two years and are not paid.

All the ANC seats were supposed to be filled during the Nov. 8 election, but in many districts there were no names of candidates printed on the ballots. This invited much write-in voting activity. Some write-in candidates won without question; but many turned out to be nonexistent, unqualified or unwilling to serve.

As staff members of the Elections Board hunted down and sorted out the candidates, they encountered one obstacle erected by the Board of Elections itself.

If the candidate who got the highest number of votes was not qualified or willing to accept an ANC seat, the board ruled, the position could not be offered to the second-highest vote-getter.

That decision, had it stood, would have meant 30 seats remaining vacant for the next two years.

ANC 6A on Capitol Hill, which had a second-highest vote-getter for one seat who was anxious to serve, appealed the decision. The Elections Board held a hearing and reversed itself.

The decision could have cleared the way for filling the 30 seats, except for a further complication. In several instances, there had been the tie votes for second place. The most dramatic case occurred in Ward 2, where eight write-in candidates tied with one vote each for seat 2C-4.

In such instances, Tuere (Ann) Marshall of the Elections Board Staff tried to contact all the candidates. After eliminating those who chose not to serve, lots were drawn to determine the ultimate winners.

Following is the list of the 26 winners eventually chosen by this process. ANCs are designated by a number-letter-number combination; the first number is that of the ward, the letter identifies the commission, and the second number is that of the individual geographic district in which the member has been elected.

1A-1, Larry Bonner, 2C-1, Charles Mason; 2C-4, Mary L. Perkins; 2C-7, Joyce Chestnut; 3D-4, Theodore Schell; 4A-5, James Walker; 4B-3, Bettie M. Holliday; 4B-8, Arthur L. Dixon; 4D-9, Virginia E. Thomas; 4D-13, John R. McCoy, 5A-13, Edward L. Feggans; 5B-9, Edward L. Minor.

Also 6A-5, Joseph Isom; 6C-2, Anita McKoy; 7C-6, Joan L. Gordon; 7C-8, Joseph F. Wood; 7D-6, Amanda J. Arrington; 7E-5, Sterling E. Fitzhugh; 7E-8, Bernice Henry; 7E-9, Junetta D. Banks, and 8B-7, Eli Rice.

Under the regular ANC law, another 26 seats for which no valid votes were cast in the election would have remained vacant for two years until the next ANC election in November 1979.

However, City Council Member Nadine Winter (D-Ward 6) introduced legislation, passed by the council and signed into law by Mayor Walter E. Washington, which provides for filling those 26 vacancies by a petition method.

These vacancies will be formally advertised Friday in the D.C. Register, the city's weekly legal publication.

Any registered voter interested in serving may obtain a petition from the Board of Elections office in the District Building, 14th and E streets NW, on or after May 3. Petitions must be returned by June 1 with at least 35 valid signatures from neighborhood residents. It will then be up to the already-sitting ANC members to choose the winners from among those who filed the petitions.

The seats involved (locations may be checked at the Board of Elections or local ANC offices) are:

1B-6, 1B-10, 1C-8, 3C-8, 4A-9, 4D-15, 5B-6, 5B-11, 5B-12, 5B-16, 6A-2, 6C-13, 7E-1, 7E-4, 7E-11, 7F-4, 8A-7, 8A-10, 8B-1, 8B-3, 8B-4, 8C-8, 8C-9, 8D-6 and 8D-7.

In addition, the Elections Board is in the process of filling by the petition method eight seats vacated by people who resigned or moved out of the neighborhoods they represented. Those seats are 1A-5, 1D-1, 2A-2, 2A-6, 2D-9, 3G-6, 7B-9 and 7F-4.