London is also building a water tunnel, but for sewage: <a href="https:&#x2F;&#x2F;www.tideway.london&#x2F;the-tunnel&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.tideway.london&#x2F;the-tunnel&#x2F;</a><p>It&#x27;s to be 25km &#x2F; 16mi long, and mostly run under the river, and should take 9 years in total to build.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Thames_Tideway_Scheme" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Thames_Tideway_Scheme</a>