Not really. Step 1: show up at suspected drug house. Knock on door. Wait for people inside to flush drugs. When someone finally does answer, ask them for information about some recent crimes, etc. Note: no need for a warrant for any of this.
Step 2: Repeat this procedure, after the dealer has had to explain to his leaders why he flushed thousands of dollars of drugs down the toilet. Again, give the dealer plenty of time to destroy his inventory and then make another social call.
Step 3: Get warrant, then start procedure the same way. But this time, dealer might not want to waste all his drugs. If he doesn't, THEN search the place.
Simple and easy. What's the problem?
If the police are executing a no-knock search warrant on someone who possesses a small enough quantity of drugs to be flushed down the toilet, I would consider that to be highly unreasonable.