More Americans own their own homes now than ever before.And, in fact, the percentage of owner-occupied houses may reach 70 per cent at the next census - after plateauing at about 65 per cent during the 1960s.

There are some fundamental reasons for this ownership binge.

The increasing affluence and broadened spectrum of people we label as middle class is one. There are simply more persons who have saved enough to make a downpayment and whose incomes are large enough to cover monthly mortgage payments.

In addition, a growing number of young, two-income couples regard home buying as a vehicle for substantial income tax deductions. They also tend to assume - based on the unusual appreciation that has occured over the last five years - that the $50,000 house purchased today will probably bring at least $75,000 on the resale market in 1982. Is there a faster way to accumulate a $25,000 gain"

In addition to the increasing aversion to paying rent for housing, there's also an increasing recognition that the rental housing stock is being depleted by conversions to condominium ownership. A free market in rental housing could have the potential of inflating prices along the lines of coffee, energy, hospital rooms and lobsters.

An estimated 3 million Americans now own or are buying second (recreation-vacation-retirement) homes. Washingtonians look not only to the the Rehoboth-Ocean City strip of the Atlantic Coast, but to Maryland's Eastern Shore, the areas south and north of Annapolis on the Chesapeake Bay and to the mountains of West Virginia and Virginia. Anita Bryant's Sunshine State of Florida took on an even rosier glow for second-home seekers during this last, frigid winter.

Homebuyers in this area are going where their pocketbooks can take them - to new apartment condominiums, converted apartment-town house condominiums (has anything sold faster than Fairlington Village or Pembrooke of Loudoun?), to two-bedroom town houses and "cluster-plex" dwellings and to mobile-manufactured homes, the latter priced well below the usual levels of urban housing.

It is not unusual to drive through a rural area and find a farmhouse with one or two manufactured dwellings nearby, presumably occupied by offspring who have married and bought a place to live - without really leaving home.

At the same time, people who already own houses are buying new or more expensive ones. Families realize that their mortgage interest payments begin to decline after 10 years in one place, and they often see an accumulated appreciation in their houses, beyond the equity acquired in paying off a mortgage, of more than $40,000.

Recent studies by the Metropolitan Washington Council of Governments and others lead to the conclusion that growing house prices are pushing segments of the urban market into dwellings that are smaller than those produced in the 1960s.

COG's study of new housing showed that the percentage of single-family, detached models with two or three bedrooms increased from 39 to 45 per cent within in one year. The growing number of young, first-time buyers in this area has greated a growing market for small, moderately-priced houses, it was noted.

One example is the strong market in new apartment and town house condominium in small clusters in Old Town Alexandria and some parts of the District, where house prices of $90 a square foot or more are not uncommon today.

Meanwhile, the new house market here is changing in another aspect. In many developments, the builder will not start a new house until a buyer is signed up. Thus, there's a wait for occupancy of at least 90 days - and sometimes 120 days or more - if the buyer is hampered by shortages of materials or key tradesmen.

Thus, a family that choses a new house today can count on moving into it at the end of the year or even next year spring, if the subdivision is sold out far ahead.

Somehow this brings back unpleasant memories of the strong selling market of 1972 and early 1973, when some signed-on buyers were forced to wait month beyond what were promised delivery dates. In that inflationary period, builders were selling houses at prices that soon turned out to be too low to make even a minimum profit of 10 per cent. Some builders then tended to daily over completing the houses, in hopes buyers would get discouraged and ask for the return of the down payments. Houses then could be sold to other buyers at higher prices. It was a seller's market indeed.

So far, the 1977 market has proven to belong to the seller once more, but builders generally seem more prepared to anticipate price increased on materials in short supply. We are also seeing another shortage of skilled craftsmen. These are signs of the housing times.

New housing has been a cyclical industry for a long time. And despite all the calls for decyclization, housing continues to hit the highs and lows and seldom finds any time to settle on a middle line.