Renée Hamidi, executive director of the Valleys Planning Council, loves to show photos of a farm in northern Baltimore County before and after 1967.

They look the same.

That’s because of the Urban-Rural Demarcation Line, or URDL — a zig-zaggy border dividing the nearly 600-square-mile county into suburban land with water and sewer service suitable for dense housing, and rural zoning that protects the air and drinking water for nearly 2 million residents of both the county and Baltimore City. Only about 85,000 residents live in the rural portion, where two-thirds of county land is located; the remaining 765,000 people live in the suburban part, on one-third of county land.

No other county in Maryland has a line like the URDL (pronounced Ur-dell), though other counties conserve land. Montgomery County, for example, has a third of its land in agricultural zoning, and Worcester County keeps 70% of its acreage in small-scale or industrial agriculture.

Developers’ calls for the County Council to shift the line have increased amid a shortage of affordable housing. Now, with the council set to grow from seven to nine members in 2026, one declared candidate — Sharonda Huffman of Essex — has joined developers in asking why the county can’t breach the line, which she calls “made-up.”

Republican Councilman David Marks has introduced legislation to make such a breach more difficult. Marks’ legislation would require a “majority plus one” vote of the County Council, planning board approval, and signoff from the council member in whose district any change would occur. The council will vote in early April on whether to put the measure before voters as a charter amendment.

Here are five questions residents have asked about the line.

The Urban-Rural line has worked for 58 years. Why does it need protection now?

Councilman Julian Jones, a Woodstock Democrat, worries that starting a debate about the line would unnecessarily open a can of worms.

The URDL preserves land — almost 70,000 acres, according to the county. It keeps stormwater runoff from development out of the Gunpowder River, which feeds the Loch Raven Reservoir that supplies the Baltimore region. The river attracts fishermen for the trout who call its clean, cold waters home. Why not just leave it be?

Marks worries new council members may sacrifice environmental protections as their constituents lament increasing housing costs. The average county home is valued at $345,967, according to Zillow, a 3.5% increase over last year. Much of the URDL is in the northernmost district, which Councilman Wade Kach represents. A stalwart URDL protector, Kach is retiring. The only declared candidate is Del. Nino Mangione, a Republican who worked in his family’s development business.

Can’t we make strategic cuts that keep most of the URDL intact but ease the housing crunch?

Protecting the drinking water supply hinges on protecting the many tiny streams that run into the Gunpowder, which is one reason planners intentionally drew a crooked line. When a watershed has more than 10% impervious surface, according to the Maryland Department of Natural Resources, the stream enters a tipping point. Fish can no longer thrive; plants can’t take up pollution effectively. Most homes within the protected area are also on wells and septic systems, which are more susceptible to contamination from construction and runoff than public sewer systems.

“If not for the URDL, much of that part of Baltimore County would be dotted with houses on 2-acre lots on septic systems — the dumbest growth possible, and it wouldn’t be affordable,” said Richard Eberhart Hall, a former secretary of the Maryland Department of Planning.

Such sprawl development, Hall said, “wastes land and related natural resources, inefficiently spreads out needs for public services and infrastructure, and pollutes more.”

Past councils have extended water and sewer service to certain URDL areas, but only rarely. While the line is not codified in county law, its protection has been a crucial element of every master plan since its creation.

Breach it once, defenders say, and developers will ask again.

“I’ve been asked numerous times to help them move the URDL,” Kach said, “and I’ve refused each and every time.”

Would opening up more protected areas make housing cheaper?

Developers have argued that building more on the rural side will increase the supply of housing, which will reduce the cost in the whole county by supplying more for the increasing demand.

But Hall, the former state planning secretary, said that’s not likely, because developers will pass on the costs of extending water and sewer lines to buyers, and because they don’t build affordable housing without significant incentives from the county or state.

“Just because land is available for development doesn’t mean developers will build affordable housing on it,” he said.

To wit: Prices in Loveton Farms, a townhouse development near the urban-rural line in Sparks, have jumped 50% in a decade. They sell for $450,000 — the cost of a single-family home in inner-Beltway neighborhoods.

Planners advocate instead for transit-oriented development. Middle River offers new housing near a MARC station. Essex would like to have similar investments, said Josh Sines of the Essex-Middle River Civic Council.

“For decades, new development has pushed further into Baltimore County’s rural areas,” he said, “while older communities like Essex have struggled with disinvestment, vacant properties and aging infrastructure.”

Councilman Mike Ertel sees a lot of vacant housing in his Towson-area district. While Baltimore City investors frequently rebuild entire blocks, Baltimore County residents go in another direction.

“As we don’t like the things that happen below us, we keep moving north,” Ertel said.

He’s referencing a familiar regional pattern. Polish and Italian residents on Baltimore’s East Side pushed north from Little Italy into Perry Hall and White Marsh; Jewish and Black West-Siders migrated from Druid Hill to Reisterstown and Randallstown.

But, Ertel asks, what happens when there’s nowhere left to push?

The Urban-Rural Line protects farms, but does it also keep Baltimore County segregated?

Less so than elsewhere. Kach’s district has the lowest percentage of Black residents, but it includes communities below the line, such as Hampton, where homes once were sold with racial covenants that barred Black buyers.

Many Towson neighborhoods also remain majority-white because of those unenforceable relics. While Rodgers Forge was an affordable streetcar suburb, racist covenants kept the townhouse community white. Families often pass down homes, so it stayed that way.

URDL zoning only allows for one house per acre — unaffordable for many people regardless of race.

Those fleeing north — to Sparks but also all the way to York, Pennsylvania — are practicing a type of self-segregation, according to real estate agent Peter Dimitriades.

He said he’s heard white buyers talk about how “Baltimore City is going to come up north.”

“There is a covert racism within that tonality,” he said.

Will the bill to protect the URDL pass?

Marks has the five votes he needs, but the council may consider amendments.

Councilman Izzy Patoka, a professional planner, favors passage, but he wants a provision to alert all members if a change is approved to allow development in the protected rural area. Every four years, the council entertains hundreds of rezoning requests; it would be fairly easy, Patoka said, to accidentally encroach on the line and weaken it.

Pat Young, a Catonsville Democrat, worries about giving one council member veto power over URDL changes in their district. Currently, all seven members practice councilmanic courtesy; they do not interfere in zoning matters outside of their district. That piece of Marks’ bill could codify councilmanic courtesy, something activists have long railed against.