Today's update includes the Water, Cleanliness, and Beauty systems! When placing an structure that affects those aspects of the town you will see a blue circle around the object letting you know which houses will be affected by placing the structure in that location. Icons will also appear over the houses letting you know which ones will get the benefit.
The town building UI also includes toggles that you can use to turn on or off the overlays on the houses for the three systems.
Gained by placing Stone Water Wells. Provides a positive mood buff for residents of a home that gain water from a well. Indicated in the town build mode overlay by a water drop icon.
Gained by placing Sewers. Provides a positive mood buff for residents of a home that are near a sewer entrance. Indicated in the town build mode overlay by a sweeping broom icon.
Gained by placing Town Trees, Wooden Lamp Posts, Stone Lamp Posts, and Stone Fountains. Provides a positive mood buff for residents near any of those decor structures. Townspeople with the "Visual" trait gain a larger buff. Indicated in the town build mode overlay by a flower icon.
The screenshot above shows the icons. The heating system will use the fourth icon slot in the upper right. Since that system actually uses resources it's a bit different from the three in today's build so I decided to work on it separately.
If you load an exiting save and have any of these structures placed, your town will automatically update the homes and townspeople traits. Just open the town build menu and turn on the overlays to see which homes have the benefits!