Despite past warnings to the contrary, the Washington Suburban Sanitary Commission told Montgomery County for the second time yesterday that a limited amount of construction may continue without risk of a sewer moratorium that would halt commercial and residential building.

The advisory was based on recalculations by the sewer and water agency showing 610,000 gallons a day left in Montgomery's share of sewage treatment capacity at area treatment plants. That is enough for about 1,500 new homes.

The extra capacity was found by finding cases of "double counting" and by reclaiming unusable sewer allocations. Last month the WSSC gave Montgomery its first reprieve by giving it credit for water conservation in figuring sewage flows.

But this relief only "moves from one expedient to another" and fails to solve the problem, cautioned John Hansman, acting director of community and economic development in Montgomery.

Meanwhile yesterday, Prince George's County Executive Lawrence J Hogan and County Council President William Amonett criticized Montgomery officials for failing to provide "substantive" responses in bicounty sewer negotiations.

In a letter to Montgomery Executive Charles Gilchrist and Council President Neal Potter, they said they "still do not know" such important information as how much treatment capacity Montgomery wants from Prince George's and how it would pay for it.