Plumbers in Maryland

Old houses, narrow pipes, hard water

Maryland’s plumbing character is set by Baltimore, which has one of the oldest housing stocks in the country. The rowhouses that define the city were built with plumbing that was perfectly adequate at the time and is now working well past its intended life.

There is a detail here that catches people out. Original supply lines in those early twentieth-century houses are narrower than what modern construction uses. Scale and corrosion take up the same absolute thickness in any pipe, but in a narrow bore that thickness represents a much larger share of the opening. So a Baltimore rowhouse loses pressure faster and more noticeably than a post-war house on exactly the same water, and by the time an upstairs shower has become unusable there is very little pipe left inside the pipe.

The water does not help. Baltimore’s supply runs around 185 parts per million, roughly nine grains per gallon, which is firmly hard. That builds sediment in water heaters and lays scale inside pipe that has already lost bore to rust.

What to do about pressure

Homeowners often assume the utility has changed something. Almost always it is internal corrosion in galvanized steel, and no amount of cleaning restores a pipe that has rusted inward. Repiping the affected runs is what returns the pressure, and in an old rowhouse it usually returns more than the owner expected, because they have been adapting to the decline for years.

On the drain side the equivalent is cast iron. It corrodes from the inside, worst along horizontal runs where water sits, until the bottom of the pipe thins and cracks. A camera inspection tells you how far along that process is, which is worth knowing before renovating a bathroom rather than after.

Lead, and how to check

Maryland is estimated to have on the order of seventy thousand lead water pipes still in place, concentrated in Baltimore City and County. That is the pipe between the main and your meter, and identification takes a minute: find where the water enters the basement ahead of the meter and scratch it with a coin. Lead is dull grey and soft, scratches to a bright silver, and a magnet will not stick. Copper scratches copper-coloured; galvanized is threaded and magnetic.

A persistent metallic taste is a reason to have the water tested rather than to speculate, and your utility can tell you what its own inventory shows for your address.

Rain, basements and the sewer

Much of Baltimore drains through a combined sewer, carrying storm water and sewage in one pipe. A heavy summer storm fills it faster than it can discharge, and the pressure relieves through the lowest connected opening in the neighbourhood. In a low-lying house that is a basement floor drain, and no amount of cleaning that drain will change it.

The equipment that works is a backwater valve on the house drain, which closes when the sewer pushes back. Where a home’s own clay lateral has cracked and is admitting groundwater, repairing or lining it reduces the load as well as protecting the house. Every plumber we dispatch in Maryland holds the state master plumber licence and pulls the local permit for work that needs one.