You do not need to water the lawn before or after an application of Talstar P and Archer IGR for fleas according to the product label. Just be sure you are using the correct amount of product per gallon of water/coverage area.
Talstar P is labeled for ticks, however we would recommend you use our Outdoor/Indoor Flea and Tick Kit for the issue that you are asking about. This kit would include everything that is needed to treat both indoors and outdoors for a ticks infestation.
Please see out Treatment Guide for more information on how to get rid of ticks.
The label advised not to exceed one ounce per one gallon of water. Talstar P is long lasting and generally does not need to be applied more than once every few months. It can be be reapplied once every 7 days at the low rate of 0.25 oz. After your first application if you are still seeing a heavy infestation you can reapply another application.
Please refer to product label for correct instructions. If your mixing rate is not per label instructions it may become ineffective.