Every so often, our house gets a letter from our senator. This started years ago, before our present senators ever got there, and while the senators have changed over the years, the formula of the letters has not. Maybe it's a benefit of living in Washington, but I prefer to get my political news from sources that don't start out with "dear constituent."

Needless to say, I usually throw the letters away without a second thought, but that is an oversight I am about to remedy. What brings this about is the news that 100 senators sent out 234 million pieces of mail last year at a cost to taxpayers of more than $48 million. A mere 4 percent of the mail involved responses to constituent inquiries. The rest were newsletters and other self-promoting missives that just happened to be considered "official business" and therefore eligible to be mailed under congressional franking privileges.

According to a recent story in this newspaper, the Senate Rules Committee has surveyed the correspondence of its members and decided, among other things, not to let the public know who is abusing the privileges the most. This is in the finest Senate tradition of not embarrassing its members. But sources quoted in the story said the greatest use of the franking privilege for "official business" was by--surprise--members standing for reelection.

But there were some big spenders who were not up for reelection, including Sen. John East, (R-N.C.) who used $1.4 million in taxpayers' money to send 6.2 million letters in the seven weeks before the election. Among his mailings that the taxpayers paid for was one in which he said the Voting Rights Act was "part of a liberal effort to rig the electoral process to suit their desires and their pet causes."

The rationale behind the free mailing privileges for senators is that it helps them inform the electorate about their activities in Washington. A certain amount of that is certainly necessary. But the Senate mailings have gone from 93 million pieces in 1979 to the current volume of 234 million pieces last year, suggesting that either the senators or the franking privilege have become badly overworked in the past three years.

The Senate Rules Committee, under the prompting of Sen. Charles McC. Mathias (R-Md.), is currently considering reform of its mailing privileges, but its idea of reform is extraordinarily limited. It is not considering cutting back to previous levels, and it is not considering tightening rules so that the taxpayers subsidize the free flow of information rather than the free flow of propaganda. No, it is merely considering capping the franking privilege at the present volume, and on Monday decided to postpone action on this modest proposal for 90 days.

If there is any overriding message coming from all points these days, it is that there is not enough money around for what needs to be done. There isn't enough money to provide food and health care and shelter for the poor, to defend the country, to safeguard the environment, and so forth. A rich and promising nation has been reduced to haggling over whom to throw out of the lifeboat next.

At the same time that the government doesn't have enough money to run the country, the taxpayers don't have enough money to run their lives. They are strapped for ways to finance their mortgages, their food bills and the education of their children. People who are making hard personal choices are not going to have a lot of patience with senators wasting their tax money on self-serving mailings.

Granted $48 million doesn't go as far as it used to, and granted the figure is dwarfed by the billion dollar figures that get thrown around in budget debates. But, pittance though it is, it is nearly twice what the United States is spending this year in military aid in El Salvador.

We have been hearing a lot about waste and fraud and cost containment in government and we're going to be hearing more of it in the coming months. The public has accepted the proposition that the money supply is finite, and having accepted that, it is going to be scrutinizing expenditures as never before. At a price tag of $48 million a year, voters are going to start reading those newsletters and realizing what they are paying for. It's one thing to open a letter and feel like a constituent. It's quite another to feel like a sucker.