How did street originate in the plumbing term street ell?

A “street ell” may have gotten its name because it describes a 90 fitting PArticularly useful in tight, street ditches. When installing water pipes under a street, or from a water service, again under the street, into a home or business, this street ell allows one to change pipe direction with one less fitting, and in less sPAce, than with a standard ell.