Private schools and their proliferation in and around the neighborhoods of Seattle have become a matter of great concern (see "School-building leases fall short," Times, Local News, Feb. 23). And it is not only proliferation in numbers but in size. Many of the reasonably well-established private schools are apparently finding it necessary to increase their enrollment. And along with enrollment, they are seeking to expand their capacity to offer special or otherwise attractive programs in an effort to compete in the marketplace.

All of this increase comes with a very large price tag to our neighborhoods and our communities.

The merits of any one of the current expansion projects may seem perfectly necessary and warranted from the "business perspective" of the school, but the fallout on the surrounding neighborhoods, on transportation systems, on parking, on pedestrians and vehicle safety, and all the support systems necessary to accommodate these institutions has become overwhelming.

Densely populated urban areas of the city are, by design, largely residential in nature and some have light commerce introduced to support and provide services. Overall, the capacities of the transportation and parking networks in these are fixed and are by all accounts already overused.

Yet, private schools are allowed to establish a foothold in these neighborhoods and then continue to grow, with seemingly little comprehensive review and consideration for their impact. They acquire more and more residential properties to meet their business-plan objectives but place unmitigated demands on the supporting neighborhoods, and remove such properties from the city tax base as they use their tax-exempt status.

The order and magnitude of these expansion projects call for a special review and a comprehensive assessment of their impacts on our neighborhoods.

Both the City Council and Mayor Greg Nickels have been presented with this challenging trend in our city. While the problems have already been demonstrated throughout many neighborhoods, the next echelon of growth is imminent.

The case has been made for a truly bold but necessary initiative: a moratorium on all private-school projects. The moratorium must, of course, be followed by a comprehensive study leading to the development of more definitive guidance in the Seattle Municipal Code targeted at private schools.

With all the emphasis and attention directed at the public-school system, it seems justified and appropriate that the private school "system" get equal scrutiny.

The mayor and the City Council will certainly play a lead role in this important citywide endeavor. Their leadership, vision and strong support are essential to bring rational and balanced planning to both private and public-school development.

Larry Hettick lives in Seattle.