FOR THE PAST nine years the District's Department of Human Resources has ordered from the federal government food intended for poor children and pregnant women - and then kept tons of it for months and, in some instances, years in a warehouse infested with rodents and insects. The result: 52 tons of canned plums, 18 tons of cereal, 14 tons of potato granules and 133,000 cans of green beans were destroyed early this year after being found unfit for human consumption.

And that's not all. Because the agency's officials failed "to promote better use of the program," DHR distributed the food that was good to only a third of the 30,000 people eligible to receive it. Of the 43 communities across the country that subscribe to the program, only Washington has had problems of this kind.

Those are some of the facts from a report by the D.C. Auditor on the agency's supplemental food program. And what has been the response of DHR officials to the document's damning charges? What you would expect: A time-honored complaint that it was all the result of not enough money, and the usual vague assurance that things will be better from now on.

Given the numerous past examples of DHR's seemingly willful violation of its mandate, we suppose we shouldn't be shocked by the latest disclosures. But how is it possible for an agency supposedly dedicated to relieving the plight of people in need to be so indifferent to poor people and so casual about its incompetence?

According to the auditor's report, DHR continually ordered excess amounts of food from the Department of Agriculture, which runs the federal program, even though it made little effort to distribute its supplies to more people. That resulted in huge stockpiles of food; for example, at the end of 1976 DHR had a four-year supply of potatoes (most of which had to be destroyed later). From the program's inception in 1963 until the recent disclosures, DHR stored the food, rent-free, in a city-owned warehouse. DHR officials say they began looking for a new facility in 1975 after an inspection revealed the presence of rats and rodents. If so, they didn't manage to find one until this spring - after a federal inspection of the warehouse caused the Agriculture Department temporarily to stop shipping the food.

The Agriculture Department has written new rules that, in the future, should eliminate inordinate stockpiling of food. But for DHR, we don't think that's enough. The Agriculture Department should order DHR - as a requirement of continued food shipments - to draw up and get federal approval of its plan for storing the food and distributing it to poor people. And it should closely monitor how DHR carries out that plan. Finally, the Agriculture Department should demand that DHR Director Albert Russo replace Doris Thornton, the DHR official who's been in charge of the program. We realize that asking a federal agency in effect to run a city program is an extreme step. But in this case, it's necessary one.