I want to know the answer to the following question:
How many km of underground passageways are dedicated to teh evacuationof Paris' waste liquids?
All the background I'm provided with is that "From then on, the new reservoir system became Paris' principal source of drinking water, and the remains of the old system, pumped into lower levels of the same reservoirs, were from then on used for the cleaning of Paris' streets.". Is that enough to answer the question?