Building Houses Evenly in Monopoly

Question

I was playing Monopoly with my friend one day and I had an orange full set AND a red full set. I started to add houses to the sets. However, as soon as I added a second house onto Vine Street/New York (the formation of houses for the oranges and reds were 1-1-2 0-0-0), my friend suddenly told me that I wasn't following the rules of building evenly. According to him, I had to build houses on the reds, i.e. 1-1-1 1-1-1, before I could start on second houses.

The properties in a color group must be developed evenly, i.e. each house that is built must go on a property in the group with the fewest number of houses on it so far.

This is what the rulebook says about building houses evenly across a colour set, however, I couldn't find anything that says that houses had to be built evenly across colour sets.

Is what I did against the rules?

Answer 1

You played within the rules. Houses must be built up (and sold off) evenly within a color group, but different color groups can be built up differently without regard to each other.

The section of the rules you quote is exactly the section that supports your play.

Addendum: not an official source, but this same question came up on boardgamegeek (with the same answer).

https://boardgamegeek.com/thread/435348/confuse-about-building-evenly

Answer 2

The rules specify that the build up only applies to the same color group. There is nothing to control what is built on properties of other groups in the rules.

Houses

But you must build evenly, i.e., you cannot erect more than one house on any one property of any color-group until you have built one house on every property of that group. You may then begin on the second row of houses, and so on, up to a limit of four houses to a property. For example, you cannot build three houses on one property if you have only one house on another property of that group. As you build evenly, you must also break down evenly if you sell houses back to the Bank (see SELLING PROPERTY).