Dashing this off from the Christmas table, so as expected most immediate Google results are the government pages. Here&#x27;s the replacement description. You&#x27;ll notice that they&#x27;re still actively replacing mains (at an extraordinarily slow rate, essentially whenever a line needs service.) If memory serves, the main line for half the city was laid during the Lincoln administration.<p>I believe the average annual replacement rate is around 1%.<p>Replacement information: <a href="https:&#x2F;&#x2F;www.dcwater.com&#x2F;lead&#x2F;scheduled_replacements.cfm" rel="nofollow">https:&#x2F;&#x2F;www.dcwater.com&#x2F;lead&#x2F;scheduled_replacements.cfm</a>