New state regulations covering the death penalty, divorce, free toilets and the sale of beer are among a host of laws that take effect today in Virginia.

The Virginia General Assembly this session added the killing of an onduty police officer to the list of crimes that may be punishable by death, and changed the method of imposing the death penalty to conform to recent U.S. Supreme Court rulings.

Under the new state law, juries will decide first on the guilt or innocence of the defendant, then, in a separate proceeding, set the penalty. The death penalty may now be imposed in the state for the murder of a policeman and for murder committed in the course of a robbery, rape, kidnaping or extortion demand, by a hired killer, and by a prison inmate.

The Maryland laws that take effect today are generally less far-reaching than their Virginia counterparts. The Maryland bill that would have had the most impact, a new death penalty statute, was vetoed by Gov. Marvin Mandel. A one-cent increase in the sales tax took effect in June.

In Virginia, two laws affecting divorce and capital punishment are among the most significant passed by the legislature.

In the area of divorce law, judges will now be required to consider the nonmonetary contribution of a homemaker to a marriage when a property settlement is written.

Thirsty sports fans will get a break under a newly passed law that makes it legal to carry beer bought at a concession back to one's seat. Under the old law (often ignored) this transport was illegal. Spectators were supposed to wait for a beer salesman to come to them or they had to quaff the beer in designated places next to the concession where it was bought.

Another new measure would require that public restrooms have at least one free toilet for each sex.

Two of the legislature's actions were of special significance for Northern Virginia. First, the legislators gave localities the power to prohibit bingo games in certain areas through their zoning ordinances. The amended bingo law also requires organizations sponsoring bingo games to limit their games to three times a week and to file audited financial reports.

The bingo reforms were prompted by disclosures by alleged irregularities in some bingo game operations in Fairfax County that were netting up to $450,000.

Secondly, in response to strong lobbying by Fairfax County supervisors, the legislature voted down a complex bill that would have allowed cities to annex land, and it extended a current state moratorium on annexations and the creation of new towns for 10 years.

The legislature authorized motorists to make a left turn on a red light from a one way street to another one way street. The turn may be made after a complete stop when no sign expressly prohibits it. The left-on-red is strictly voluntary. Legislators enacted the law to save time and gasoline.

Other automobile-related laws that become effective today require that drivers injured in an accident (as well as those not injured) must now make a report to police as soon as possible; would make inspections unnecessary for boat or utility trailers up to and including 3,000 pounds that do not have brakes; would extend the validity of drivers' learning permits from six months to a year, and would allow police to join their colleagues in the District in using the "Denver Boot" to immobilize parked cars with three or more unpaid traffic tickets.

Police will also henceforth be able to charge persons with drunk driving it, while intoxicated, the mode of transport is a motorized bicycle (moped). Motorists will also be prohibited from covering both ears with earphones.

In other matters, the legislature made a sweeping revision in the juvenile offender's code, decreeing that so-called "status offenders" - truants, runaways, those who chronically misbehave, but have not committed criminal acts - can no longer be kept in correctional institutions with adults unless the nearest juvenile facility is more than 25 miles away. The new law is going to mean that localities must expand or build new juvenile facilities.

A mandatory sentencing act for repeater felons will require that offenders serve an extra year for a second offense, an extra three years for a third offense and an added five years on a fourth felony conviction.

But ex-convicts will get a break when searching for a job under a new state regulation that bars state and local agencies from considering their criminal records when they apply for a professional license - if it is for a line of work unrelated to their previous offense.

And victims of violent crimes can begin to apply to the state for compensation of up to $10,000 for medical bills, disabilities and loss of work resulting from violence. The compensation results from a 1976 law that will become effective July 1.

Landlords will henceforth be required to return a security deposit if a tenant changes his or her mind about renting an apartment, but landlords will be allowed to charge an application fee. In apartment complexes of more than five units, the landlord must install peepholes and dead-bolt locks on a tenant's door if he or she requests it - but at the tenant's expense.

In a concession to energy-consciousness, the assembly authorized the state Board of Housing to give loans to homeowners installing solar or other alternative energy devices. Localities may also give property tax exemptions to homeowners who install such devices.

Of the more than 800 new laws that go on the books in Maryland today, the most controversial is a portion of the budget bill for state government under which the state will finance the conversion of Baltimore's abandoned Continental Can Co. factory into a prison designed to house 890 inmates.

For the rest, "it just wasn't too big a session," said Carl Everstine, director of the state department of legislative reference.

Assiduous lobbying during the legislative session did produce laws that will benefit two distinct groups of Maryland citizens: the elderly and the handicapped.

The price of a large number of prescription drugs, which often are a necessity for older people, will probably be reduced by the enactment of a measure increasing a pharmacist's ability to sell their customers lower-priced drugs that are generic equivalent of the higher priced brand-name drugs.

An earlier law had allowed pharmacists to do this with about 100 drugs. That number will now be more than 4,000. Pharmacists may substitute the generic drugs in almost all cases, unless the customer's physician specifically directs otherwise.

And, as of today, Maryland's mentally retarded citizens will have the right to live in group homes in residential areas without requesting special approval from local zoning boards.