Correct Option (2)
The passage explicitly states that sustainable water delivery requires significant investment not only in collecting, treating, and distributing potable water to users but also in sewerage infrastructure and sewage treatment plants. The purpose of these additional investments is to ensure that no untreated sewage is discharged back into natural water bodies. This comprehensive description indicates that sustainable water delivery encompasses a broader scope than merely supplying water to households, extending to the complete management of wastewater. Therefore, assumption 2 is valid.
Incorrect Options:
The passage mentions, "If our cities were rich enough to meet the entire cost, water could be delivered free. They are not." This statement highlights the financial constraints faced by urban bodies and the necessity for financing mechanisms. However, it does not imply that only rich cities can ensure sustainable water delivery. It rather points to the challenge of covering the full cost of services and the need for viable funding models, which could include various approaches beyond a city's inherent wealth. Thus, assumption 1 is not a valid inference from the passage.