Here are a few items to consider.
1. Track Record. There are many independent review sites available online that will give you a critical point of view from past customers. This is a good first step in narrowing your search. The Better Business Bureau is also a good point of reference.
2. Business Longevity. It's really important to use an established house cleaning service. The longer they've been in business the more positive response you should find for the business in the community. It also helps if they have the seal of approval from a national organization in the business.
3. Accredited, Certified and Licensed. Any business you invite to come into your home should have these items in place. It protects you from bad business procedures and it protects the company from false claims. It also means that you have a quality of assurance that they'll do the job right the first time they come to your home and that their cleaning staff is bonded.
4. Types of Chemicals. Some people have an aversion to certain chemicals, be it smell or touch. Make sure that they use only the safest techniques to clean your home from top to bottom. Harsh detergent use cannot only harm you but the inside of your home as well. A little internet research on your part will help you determine what type of cleaning solutions to avoid and which ones you'll feel safe with.
Besides these suggestions, you might want to narrow the field down to incentives offered from each company. Today most online services offer discounts on the first visit. It might be wise to find a company that doesn't try and sign you to a binding long term contract. Life situations change and you don't want to pay any back end costs to get out of a contract. Likewise, make sure that all pricing is in place before your chosen house cleaning Carlsbad CA service begins work. Not many, one or two, might try to "up-sale" you before they finish. This is not a good policy and you should make sure upfront that everything is in writing.
The best way to find the company right for you is with an internet search using keywords like, cleaning services Carlsbad ca or house cleaning Carlsbad ca. In this way you should be happy with the results.