Mold inspection and indoor air help in Santa Maria, CA
We do not keep an office in Santa Maria. Every job starts with a free call. For large and complex properties in the Santa Maria area we travel to you; for smaller jobs we tell you exactly what to ask for and point you to a local inspector we are comfortable recommending.
What the Santa Maria climate does to a house
Measured at NOAA's Santa Maria weather station.
- At the NOAA Santa Maria station, mornings average 75 percent relative humidity across the year, and afternoons 63 percent.
- The dampest mornings come in August, averaging 80 percent. Afternoons are driest in December, at 61 percent.
- A normal year brings 13.95 inches of precipitation over about 46 days, with the most in February (2.99 inches).
- In 1 of 12 months the average morning humidity is 80 percent or higher.
- Even in the afternoon, average humidity stays above 60 percent in 12 of 12 months. Indoors, 60 percent is the line where mold starts to find it easy.
| Month | Morning RH | Afternoon RH | Precip. (in) | Days with precip. | Mean temp (°F) |
|---|---|---|---|---|---|
| January | 72% | 63% | 2.75 | 8 | 51.5 |
| February | 75% | 64% | 2.99 | 8 | 52.8 |
| March | 75% | 64% | 2.64 | 7 | 54.0 |
| April | 74% | 62% | 0.98 | 5 | 55.6 |
| May | 77% | 63% | 0.31 | 2 | 58.0 |
| June | 79% | 64% | 0.04 | 1 | 60.5 |
| July | 78% | 64% | 0.03 | 0 | 63.2 |
| August | 80% | 66% | 0.02 | 0 | 63.7 |
| September | 77% | 65% | 0.14 | 1 | 63.2 |
| October | 71% | 64% | 0.60 | 2 | 60.9 |
| November | 69% | 63% | 1.33 | 5 | 55.8 |
| December | 70% | 61% | 2.12 | 7 | 51.2 |
Source: NOAA National Centers for Environmental Information, Comparative Climatic Data: average relative humidity (period of record through 2018), normal precipitation, mean temperature and cooling degree days (1981 to 2010 normals), and mean days with 0.01 inch or more of precipitation, 90 degrees or more, and 32 degrees or less. Last updated September 27, 2026.
Where moisture hides in Santa Maria homes
Plumbing leaks nobody sees
In a dry climate, mold is almost always a water event, not humidity. Slow leaks under sinks, behind dishwashers and in slab plumbing can run for months before anyone notices. Afternoons here average just 63 percent humidity, so damp air is rarely the cause.
Short, violent storm seasons
When the rain does come it comes hard. Roofs, parapets and flat-roof drains that sit dry most of the year fail all at once. Only about 46 days a year bring measurable precipitation, most of it in February.
Evaporative coolers
Swamp coolers cool by adding water to the air. Poorly maintained ones add humidity and their own microbial growth to the house. 5 days a year reach 90°F or more, which is when coolers run hardest.
Pools, spas and irrigation
Water features and landscape irrigation next to the foundation keep one side of a house damp in an otherwise dry place. A normal year brings only 13.95 inches of rain, so irrigation water often outweighs rainfall at the foundation.
Common questions from Santa Maria
Large, custom or multi-property situations: see Keystone.
Mold or air problem in Santa Maria?
Start with a free 15 minute call. We will tell you what you need, whether that is a local inspector, a virtual consultation or an on-site investigation.