Maryland lawmakers are considering housing, health and other guidelines related to the pesky problem of mold. But if you think you’ve got mold in your home now, how do you know when you should do something about it?

Here are some frequently asked questions that could help determine when your mold problem is more than just a nuisance.

How do you know if you have mold?

If there is moisture in your home, there could also be mold. Some mold can appear orange, white, brown or black. But other times the spores may not be obvious, especially if they are hidden in the HVAC system or in the walls.

If you are uncertain, you can contact your landlord or a licensed home inspector who is certified to conduct mold testing. Officials at the Baltimore City Health Department also say residents can call 311 for an inspection of the property.

How dangerous is mold?

Experts say there isn’t enough research to know how long-term exposure to a lot of mold affects people, though people come into contact with many types of mold inside and outside and they agree this likely isn’t much of a threat.

Still, some people are allergic or more sensitive to the presence of mold, which can affect people differently, causing headaches, allergies or sparking asthma attacks. People who are immunocompromised are thought to be more sensitive to mold than others. But effects from long-term exposure aren’t well understood.

The U.S. Environmental Protection Agency says mold can produce allergic reactions or lead to potentially toxic substances if it comes into contact with food. The agency also said it can irritate the eyes, skin, nose, throat and lungs in both mold-allergic and nonallergic people.

How can you clean it?

The EPA recommends fixing all possible plumbing leaks and water problems as soon as possible to assist with cleanup efforts and drying surfaces completely. Mold can be scrubbed off hard surfaces with detergent and water, but some surfaces such as carpets may have to be thrown away if they become moldy. Specialists in furniture, art and painting restoration, or carpet and rug cleaning professionals, may be able to help.

The EPA advises that those who attempt to clean mold by themselves wear well-fitted N95 respirator masks, gloves and goggles.

When should you call a professional?

Hiring help can be costly, but the EPA recommends using a professional when a moldy area is greater than a roughly 3-by-3-foot patch.

A professional should also be contacted when there is mold or water damage in the heating, air or ventilation systems, according to the EPA, as well as when you suspect the water and/or mold damage was caused by sewage or contaminated water.