In the very early collection systems (especially for “separate” sanitary sewage systems), narrow lamp-holes were installed for visual inspections of sewers, but it soon became clear that they were almost useless as a maintenance access point. Manholes corrected this problem, providing access to the sewers for inspection and cleaning. A second purpose of manholes was to serve as points of ventilation for the gravity sewers. (It was recognized early on that sewers need to “breathe.”)

There are many types of manholes used at one time in the sewer system, including drop manholes, wellholes, and “flight” sewers. Many of these designs can be seen below.

See Tracking Down the Roots of Our Sanitary Sewers for more information.

Baldwin Latham, C.E., M. Inst. C.E., Sanitary Engineering, A Guide to the Construction of Works of Sewerage and House Drainage with Tables for Facilitating the Calculations of the Engineer (New York: Engineering News Publishing Company, 1884).

See page 45.

PDF of all chapters (17 MB)

PDF of map of Dantzic (Gdansk, Poland) (Plate I, 5 MB)

PDF of illustrations only (Plates II to XIX, 4 MB)

W. G. Kirchoffer, “Novel Sewerage and Sewage Treatment Plant
at Mt. Horeb, Wis.,” Municipal and County
Engineering
, August
1918, p. 61.

PDF version (printer-friendly).

1920 catalog from the predecessor to Neenah Foundry Co.: Aylward
Sanitary Iron Catch Basins, Catch Basin Inlets, Manhole and Lamphole
Covers, Track Drains, Crossing Plates, Lighting Standards, Special Castings
from Drawings
, (Neenah, Wisc.: Aylward Sons Company, 1920), cover,
pp. 1-8, 21-23, 30.

PDF version (printer-friendly).

Grant M. Olewiler, “Sewer Maintenance,”
Sewage Works Journal, Volume IX, No. 5 (September
1937), pp. 808-820.

PDF version (printer-friendly).

U.S. Patents
Patent for sewer basin, 1861. Patented by William H.
Short on April 9, 1861. U.S. Patent No. 32,008, pp. 1-3.Source: United States Patent and Trademark Office at http://www.uspto.gov.

PDF version (printer-friendly).

Patent for manhole and cover, 1878. The pan cover was
filled with wood or rubber blocks to street level. Patented by Thomas
Kerr on March 19, 1878. U.S. Patent No. 201,349, pp. 1-3.Source: United States Patent and Trademark Office at http://www.uspto.gov.

PDF version (printer-friendly).

Patent for a means for preventing the accumulation
of gas in manholes, 1891. This device also helped prevent ice buildup
that froze manhole covers in place. Patented by Charles W. Hays on August
11, 1891. U.S. Patent No. 457,436, pp. 1-3.Source: United States Patent and Trademark Office at http://www.uspto.gov.

PDF version (printer-friendly).