Available data indicates that; 1) electricity usage for water pumping at homes is minimal; and 2) most municipal water systems provide more pressure than required for residential uses
Is it common for people on city water in the US to have their own on-site pumping as part of the "standard" delivery system?
The U.S. Energy Information Agency's 2015 "Residential Energy Consumption Survey" (RECS) includes data on electricity end use by category:
Water pumping is not a specific end-use category, so would be lumped in the 13% of "not elsewhere classified," which would also include rural homes that pump their own well water. We can assume that across all homes, water pumping doesn't represent significant usage, otherwise it would likely have it's own category. So pumping water is probably going to represent less usage, on average, than each of these (source):
||kWh per house per year using the end use
|Hot tub pumps
Or is the pressure usually entirely supplied by the municipal infrastructure/water towers etc?
Data on municipal water supply pressure standards is hard to come by, but a 2016 paper from the American Society of Civil Engineers provides some interesting details: "Pressure Standards in Water Distribution Systems:Reflection on Current Practice with Consideration of Some Unresolved Issues".
It would seem that most water delivery systems (WDS) in the U.S. supply sufficient pressure for residential uses because there is a higher-pressure constraint: fire flow. Fire flow is water drawn by sprinkler systems and fire hydrants, which require a certain minimum pressure in order to function properly. In fact, meeting fire flow requirements can cause other problems (emphasis added):
Although a [minimum pressure constraint] is enforced in WDS design to ensure supplying adequate demands during periods of peak consumptions (e.g., the greater of the maximum hour demand and the maximum day demand plus fire flow), many systems experience higher pressures than necessary during off peak demand periods. This is so much so that, in certain instances, residential customers might need to install pressure-reducing valves in their homes.
A 2014 paper found that most utilities agree on a minimum pressure requirement, but don't track high pressure events. From "Survey of pressure management in water distribution systems":
Although the majority of utilities recognize the need to maintain distribution system pressure of at least 20 psi under fire flow and emergency conditions, most have no goals to control high pressures in their distribution systems. As a result, their systems are at increased risk of water loss, main breaks, and infrastructure deterioration because of the lack of an effective pressure management system.