I recently excavated a couple of cisterns at Fort Johnson, Charleston SC (38CH69.com). They didn't have filters, but I did find a number of patents using Google patents and found a wide variety of styles, including the pierced stoneware type someone else mentioned.
Carl Steen
-----Original Message-----
From: [log in to unmask]
To: [log in to unmask]
Sent: Thu, 10 Apr 2008 9:58 am
Subject: Re: Cistern filters
At Mission San Antonio de Padua in California there is a reservoir with a
small settling basin attached to it dating to ca. 1800. The basin has a square
floor tile set upright in the wall, with holes punched throough it. This
served as a filter to remove large matewrials before entering an underground
ceramic pipeline. A Spanish construction that is pure Roman in detail.
Bob Hoover
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