The year at a glance

January
Cold snaps peak. Check attic sheathing near bath fan ducts for frost from the hatch, wipe window condensation, and lower the furnace humidifier during extreme cold.
February
Look behind stored items in closets on north walls and in basement corners. Test water leak alarms.
March
Heavy wet snow is common. After it melts, check window wells, downspout outlets, and basement walls next to where snow drifted.
April
Clean gutters after spring winds. Inspect grout and caulk in every shower and tub.
May
Before turning on irrigation, check sprinkler heads near the foundation and adjust any that spray the house or window wells.
June
Start the air conditioner and confirm the condensate line drains. Hail season: inspect the roof and gutters after storms.
July
Afternoon thunderstorms bring brief heavy rain. Check basement window wells and the sump pit after a big storm.
August
Check the condensate pump and the floor around the furnace. Look under kitchen and bathroom sinks.
September
Inspect the water heater for rust or seepage at the base, and note its age.
October
Blow out irrigation lines before the first hard freeze. Disconnect hoses and check frost-free hose bibs for drips inside.
November
Replace the furnace filter, service the humidifier, and run each bathroom fan to confirm air exits outside.
December
Keep holiday cooking and guest showers vented. Watch for condensation on windows in rooms with doors closed.

Tools that make the calendar easier

  • An inexpensive digital hygrometer for the basement and one bedroom
  • Battery-powered water leak alarms for sinks, the water heater and the washer
  • A bright flashlight for attic and cabinet checks
  • A notebook or phone note to log readings and dates
  • A moisture meter if you want to track a suspect wall

Useful targets

Indoor humidity, most of the year
Many sources suggest roughly 30 to 50 percent
Indoor humidity, extreme cold
Lower end of the range to limit window and attic condensation
Bathroom fan run time
During showers and about 20 minutes after
Water heater check
At least yearly, more often once it is over ten years old

Common questions

Why does a dry climate need a mold calendar at all?

Colorado's dry air helps exposed surfaces dry quickly, but most mold problems start where water is trapped: behind finishes, under cabinets, in attics during cold snaps. The calendar targets those trapped-water moments.

What if I miss a month?

Catch up the next month. The checks that matter most are the bath fan test before winter, irrigation adjustment in spring and the air conditioner drain in early summer.

General information for Highlands Ranch, not a quote or professional advice. In an emergency, call 911.