I think the general rules are that the open or community rooms decor & finishes in a home should ”flow’ from one to the other. The closed off to the public / daytime living rooms - bedrooms, master bath etc don’t need that flow. Your powder room sounds like it’s inside another room - the laundry room. How open is your laundry room to guest view? Is the laundry & powder one large room or is Powder a separate room inside laundry room? If you pass through laundry to get to powder or if powder & laundry are actually in the same room, to me, that means I’d be snazzing up my laundry room with nicer finishes etc & Powder room might share some of the colors or finishes. So, no I don’t think a white vanity in Powder room is necessarily an issue - what’s in the laundry room?

You do walk into rhe laundry room to access the powder room, which of course, has its own door.  The laundry room houses my washer and dryer but also my water heater and heater. It's quite narrow. The floor in that eoom could use replacing, as well .  I do have a tall white pantry type cabinet in the laundry room for cleaning supplies but the wood shade in the laundry room is kind of a chestnut color.

@Michelle S. If you post pics of both laundry & powder rooms you’ll likely generate specific design / style suggestions. Since your laundry floor ’could use replacing’ it’d be nice if same flooring used for both rooms - waterproof of course. That’s a nice ’flow’. And, a white vanity with pretty countertop would be good too since the laundry cabinet is white - maybe match the cabinet door hardware too? Is there a way to screen off the heaters from view? Even just a standing floor screen of a wood matching the blinds? Since guests need to walk through laundry to powder room, I’d want the laundry room to be glammed up a bit too. Win - win since that makes laundry chores more pleasant!

The laundry room is very utilitarian.

Some choose the powder room to be very different from the rest of their home decor. Others choose to have their powder room coordinate with the rest of their home look. For example: I wanted my bathroom / laundry room to coordinate with my kitchen ( as these rooms are next to each other). My kitchen has light grey cabinets and darker gray counters; I chose the bathroom / laundry room to have a charcoal vanity and white counter. Both rooms have the same oak flooring.