What you're providing is really babysitting vs. formal childcare, so I'm not sure it's regulated by the state. However, a quick search of the Texas DFPS site brought me to this FAQ page, which indicates that one adult per every four children is the required ratio, at least for employer-provided daycare. I hope that helps.
- Craig
Links in this post:
this FAQ page: http://www.dfps.state.tx.us/child_care/search_texas_child_care/faq.asp