Insights
Under the street
How often the cities Subsola maps dig up their streets, who does the digging, and what's buried down there. Every figure comes from the cities' own open data, recounted each night.
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Headline
of digs on a New York City block are followed by another dig on the same block within a year. In Washington, DC, it's .
How soon a block is dug again
A dig here is one company's permits for one utility on one block, with permits less than 30 days apart counted as one dig. Half the time, the next dig on a New York block comes within days. In DC it's days.
Los Angeles and San Diego are left out of the dig charts. They file one permit per job, often for a whole street rather than a block, so a repeat there says more about how permits are filed than about digging.
A different utility, back within 90 days
In DC, of digs started within 90 days of a dig on the same block by a different company working on a different utility. In New York it's . Each of those is a street patched and then opened again.
The most-dug blocks
has been dug times since , by crews doing kinds of utility work.
Each city's records start in a different year, so compare blocks within a city.
Who digs in New York
Con Edison holds of New York's street-opening permits since . National Grid, which also files under its old KeySpan and Brooklyn Union Gas names, holds .
National Grid's KeySpan and Brooklyn Union Gas filings are counted as National Grid. Permits filed under names that may be a person's are grouped and not shown.
What's buried down there
By length, of San Diego's water mains are , of Los Angeles sewers are , and of Seattle's water mains are . Half of Seattle's mapped water mains went in before , and of Denver's sanitary sewers are .
Pipe material by share of length Each city publishes different pipes. New York publishes no main locations at all.
Lead pipes into buildings
New York, DC, San Diego, Seattle and Denver publish an inventory of the service lines that run from the water main into each building. In New York, of tax lots, of them, still have a lead line. San Diego's inventory of meters lists lead lines, and Seattle's services list . Denver Water confirms lead lines among the Denver premises in its inventory.
Each city counts differently. New York counts tax lots. DC counts premises and shows only lead it has verified; suspected lead is under not yet known, and DC Water files galvanized pipe under lead rather than apart. San Diego counts water meters. Seattle publishes only the material of its own part of each service, up to the owner's pipe, and no lead classification. Denver Water counts premises, files galvanized pipe downstream of lead under lead, and puts the lines it calls likely lead under not yet known. Galvanized pipe can carry lead it picked up from older pipe upstream.
How these numbers were counted
- Permits, not shovels
- A permit is permission to open the street, not proof that it was opened. Permits that never cut the street, such as New York's permits to open a manhole or store material, are left out.
- One dig
- One company's permits for one utility on one block, with permits less than 30 days apart counted together. The one-year share leaves out digs from the last year of records, and the three-year share the last three, since what came after them can't be seen yet.
- Cities left out of the dig figures
- Los Angeles and San Diego file one permit per job and often place it on a whole street rather than a block, so their digs aren't comparable and aren't charted.
- Years covered
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The years each city's permits cover in earnest, from the first year with at least a
tenth of its busiest year's permits:
- Pipes
- Shares are by length of the pipe each city maps today. San Diego and Seattle publish water and sewer mains; Los Angeles and San Francisco publish sewers; DC publishes water mains 16 inches and larger. Seattle's water layer holds only distribution mains, 10 inches and smaller. Denver publishes sanitary sewers and storm drains, and Denver Water no mains. New York publishes no mains. Install years are as recorded, and half the dated length is older than the median year.
- Lead service lines
- Counts only, no addresses: New York DEP by tax lot, DC Water by premise, San Diego by meter, Seattle Public Utilities by service and Denver Water by premise.
- Sources
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Figures as of , from the nightly build of the map's data.