If we have whole house HRV/ERV with inlets in bathrooms, do we still need exhaust in bathrooms?

that's still up for discussion. Some builders use both; others use only the HRV. I've built several homes with only an HRV, and, while I'm often told it won't work, it does. No homeowners have complained about excessive moisture remaining in the bathrooms and there aren't any signs of problems. I assume the fact that the HRV is always on means that over time the moisture is adequately vented, although it may take a couple of minutes longer than a dedicated higher speed fan. I do use booster switches in the baths which boost the HRV fan to high speed. (By the way, I'm in climate zone 6)

Thanks. We are in Sunnyvale/Cupertino area (Silicon Valley). Zone 9.

-lm

Modes codes require bath ventilation and are specific about CFM for mechanical or size of opening vs SF for natural ventilation.
They generally prohibit recirculation as well.
That said they care little about mechanical system employed. Inspector level of education can be a factor as well if a system is not familiar to them.

I have an 120 cfm ERV going into a four way distribution box ducted to two baths, the kitchen and a laundry closet, Light switches in each location work power-open registers with termination switches (i.e. when the register opens fully it turns on the ERV.) In other words, a demand switch pulls all 120 cfm from any of the four locations. I have a fifth register in a central chase that works the ERV on a timer for air exchange. Three caveats: Because they don't need defrosting, ERVs make more sense than HRVs for venting a bath in a cold climate; My manufacturer, Renewaire, says the kitchen register can't be closer than 10 feet to the cooktop; In a house full of kids, you'll have some real optimization problems. An ERV won't move moisture effectively unless the two airstreams are balanced, and doing so in my scheme is impossible. I have it balanced for air exchange on the timer. The missus and I don't use the ERV on demand but a couple times a day.