Peak factor within the maximum day The ratio of maximum hourly consumption to the average hourly consumption on the maximum day is commonly taken as:

Introduction / Context:
Water-demand patterns vary through the day. Designers adopt a peak-hour factor relative to the average hour of the maximum day to size mains, pumps, and storage prudently.

Given Data / Assumptions:

• Typical urban consumption without extreme industrial spikes.
• “Maximum day” refers to the day with the highest 24-h demand in the design year.

Concept / Approach:
Standard planning values often take the peak hour on the maximum day as roughly 1.8 times the average hour of that same day. This reflects morning/evening peaks and supports sizing to avoid excessive pressure drops during short spikes.

Step-by-Step Solution:
Define peak-hour factor F = q_max,h / q_avg,h(max day).Adopt the commonly used figure F ≈ 1.8.Select 1.8 from the options.

Verification / Alternative check:
Waterworks manuals list ranges (1.5–2.0); 1.8 is a frequently cited exam value for Indian and many international contexts.

Why Other Options Are Wrong:

• 1.2 and 1.5 underestimate peaks; 2.4 and 2.7 are unusually high for general planning.

Common Pitfalls:
Confusing this factor with “maximum day to average day” ratio; both factors are used but represent different planning levels.

Final Answer:
1.8