Poland's winter drought hits an already parched economy.

A winter drought is serious in its own right. In Poland, it could spell social unrest. The drought is an added threat to an already very serious economic situation in Poland - one that is in many ways graver than at any time since the Solidarity crisis erupted four years ago.

If there is no substantial and visible improvement and no relief for ordinary consumers soon, this situation could easily become political and create a new dimension of social unrest.

Since October, rainfall and snow in vital agricultural areas have been less than half of normal. Thirteen of the country's major water reservoirs are only 37 percent full.

The government is making contingency plans for water rationing. It says that unless there are bounteous rains this spring, at least 2 million tons of autumn sown grains could be lost.

Not all of the blame can be pinned on nature. There are persistent and unresolved faults in the Polish system. Though last year saw some economic growth after several years of recession, the underlying causes of deficiencies in almost all branches of the economy remain.

These have more to do with the economic system than with the effects of sanctions - even if Polish estimates of the sanctions' cost are accurate. But these fundamental problems are still not sufficiently recognized, as the slow progress with the economic reform suggests.

The government is calling for a tremendous export effort. But low productivity, quality, delivery, and other problems make Polish exports uncompetitive in the markets that matter most - the West. And it is unlikely that Poland can regain markets lost in the crisis years.

The Ministry of Labor reports that still little more than 60 percent of working time is utilized. It cited an International Labor Organization study showing that Poles work on average only 34 hours in a supposedly 42-hour week, while in countries like Japan and France and even one of Poland's allies, Czechoslovakia, actual working time reaches 40 to 43.5 hours.

Many enterprise managements think only of the domestic market and allow wages to rise regardless of poor and even declining productivity. Overtime on the supposedly ''free Saturdays'' and on Sundays doubled last year, adding as much as 50 percent to wage bills.

But how can the workers be blamed, when incentives remain so limited and their economic prospects so bleak? The average monthly wage is up to 16,000 zlotys (after the recent devaluation, about $150). But inflation is unchecked and living costs rising.

Food shortages are not so bad, relatively speaking, but there are still shortages of many ordinary essentials. For example, people must queue for hours before a store opens to get the textile goods they need.

Any apparent easing of the situation is still superficial. At the recent Communist Party conference, it was stressed that economic reform needed to be implemented more quickly. But it is still a slow, piecemeal operation.

In major sectors, anti-reformers contrive, often successfully, to thwart the process. The labor minister may insist that better work must be rewarded with better pay. But there is still a strong lobby for egalitarianism. It was an ill-judged Solidarity demand in 1980. But many workers stick to it, even though it is obviously against their own interests in the longer term.

Economic recovery is still at an emergency stage. Few independent observers here believe that recovery can continue much further unless the West lifts its economic sanctions or international agencies provide some help.

By the end of this year, Poland's debts to Western governments and banks could top $29 billion, the Finance Ministry said recently. Commercial banks are well into talks about further rescheduling. And creditor Western governments engaged in a second round of preliminary talks in Paris late last month.

This time, the United States may take the European view that sanctions are increasingly counterproductive for the West itself, as the banks have already concluded.

Polish officials insist they have met US preconditions for ending the sanctions by lifting martial law, freeing almost all of the political detainees, and legislating for the Roman Catholic Church's agricultural aid plan. The remaining political prisoners have been offered ''temporary'' exile abroad, but they have rejected this option so far. It is said they may be released if they promise to stay out of politics. Presumably, either option - provided it was ''voluntary'' - would satisfy the US.