Though this isn't my area of law, I think most counsel would agree with me that mold, which has an ability to turn the apartment "toxic", is a landlord's responsibility. Your duty as a tenant is to notify the landlord promptly and allow a reasonable period for repair/redress. If the landlord fails to act and the apartment becomes inhabitable, you may have no option but to advise that you will seek a company to fix the problem and deduct the funds from your next month's rent. If it does get to that point, I suggest seeking legal counsel to possibly terminate the lease.
For purposes of this question, please let me assume that the mold has not been caused in any way by you.
First, notify your landlord about the mold IN WRITING. Notification must be in writing to preserve your rights and start the clock ticking on the maximum time your your landlord can take to clean-up the mold. Your landlord is responsible for the permanent removal of mold that has not been caused by you.
Second, clean up as much as you can to keep the mold away from your children (children can be particularly susceptible to health problems caused by inhaling mold spores) and your personal items.
Third, when the landlord sends in the cleaners, make sure the cleaners have experience permanently removing mold, and ask the cleaners to make a determination of how bad the mold is and what caused it. It's likely that if the mold has penetrated your carpet, drywall, or woodwork, those items will need to be replaced, not just cleaned.
During the time you are inconvenienced, you can make arrangements with your landlord to have some or all of your rent credited, depending on the nature and duration of your inconvenience. Check your rental agreement for guidance on that (if the agreement addresses that issue). Make sure you have an agreement for paying "short rent" in writing before you pay less that your rental agreement requires. That way you preserve your rights and your landlord can't claim you are in breach of agreement.
If you feel you deserve a substantial rent credit and your landlord won't give you a credit, OR the landlord won't clean up the mold, you may want to consider hiring an excellent attorney to help you get a credit or get the landlord to perform the clean-up. In the alternative, you may want to give notice to move out as you have likely been "constructively evicted." Again, an excellent attorney can help you with the details of moving out.
Mold is potentially highly damaging to certain people's health, and to your personal property. Don't wait to take action.
Good luck, and all the best. Mark Arend
The previous posters have given you good advice. The only thing I would add is that you could have an engineer come look at your mold, figure out what it is and where it came from.
Darrell Cochran in Tacoma just wrapped up a case against the Pierce County Housing Authority about mold. You might want to contact him.
There is a specific way to get the County to come inspect and determine whether the problem is so severe that you should be compensated by your landlord. I've published a legal guide here on that approach.
But the bottom line is that you don't want to expose your family to the effects of toxic mold, so find out what you have and take action one way or another. Hope this helps - Elizabeth Powell