MOST PEOPLE IN MONTGOMERY ans Prince George's counties seem to be coping with the water crisis well, despite the costs in terms of cleanliness, convenience and comfort - and despite some confusion about how serious the situation really is. If repairs at the Washington Suburban Sanitary Commission's pumping station proceed as planned, this week's dire shortages, business shutdowns and fears about fire protection will not last long. but that won't be the end of the area's water problems. Because of sparse rainfall, the Potomac River has dropped to about a foot above the critical level for the WSSA intake. If the drought continues, the Maryland suburbs could have their pumps in perfect working order - and still find themselves high and dry.

While water-supply problems for the Districct and Northern Virginia are not quite as immediate, no one has reason for complacency. Fairfax County officials are edgy, for example, because the Occoquan system's capacity is limited and the quality of that water is a matter of constant concern. The Fairfax plan for a Potomac intake - like the long-planned low dam to help WSSC - has been blocked by the Corps of Engineers, which is using its veto power to protect the interests of its own customers in the District and Arlington.

In our view, there is only one way to cut through these tangles and make all of the region's water systems less vulnerable to accidents or drought. The key step is political: Everyone involved in water policy here will to agree, finally, that this is a regional problem and must be dealt with as such.

To stat with, everybody will have to accept the principle that, as far as possible, all water users in the region, including newcomers, should be treated equally, and that the burdens of any shortages should be shared by all. If the Corps in particular would adopt this broader view, an accord could be reached quickly on how to allocate Potomac water in periods of low flow. That agreement, in turn would largely clear the way for the WSSC and Fairfax projects, thus relieving the threat of serious shortages in those areas.

In exchange for greater access to the Potomac, the suburban water agencies should be willing to share the water in their reservoirs when the Potomac's flow is inadequate. This approach, set forth recently in the so-called Sheer report, is being analyzed in detail now. The pipelines involved would not be cheap, and some technical aspects are complex. However, it seems to us that such water-sharing, coupled with area-wide water-saving programs, makes a great deal of sense. It may be the only alternative to a series of local crises and quarrels over water in the years ahead.