Can you flush roots zone with tap water?

I been feeding with rain water all ways done it it’s all I use I do flush every 4 feeding Just something I do I see lots of people use tap water to feed their plants my question is will it mess up my grow if flush with tap water ? I have 3 gallons ready to flush but ppm 401 ph 9.2

I am far from an expert, but in my opinion you should not use anything that has a PH of 9.2 on your plants.
If you were to use the tap water, it should most certainly be PH'd first.
As far the 401 PPM level, it may be totally harmless, but it might also be something that would not be good for your plants.
That's the thing about the unknown...it's unknown.
Unless you have your tap water tested, there is no way to know what is in it, or whether or not is would be harmful or helpful.
One last point, when you read about others using tap water, their tap water may be at 6.0 PH and 37 PPM, in other words perfect of their plants.

Good Luck with your Grow,
WillieP

If that is soil you're growing in then you probably shouldn't be "flushing" (depending on what you actually mean by that).

But yeah...a pH of 9 isn't great in any grow, so I'd probably not use that to water with regularly.

I’m in soil I use advance nuts and I. Feed only water ph every 4 feeding so I don’t have to worry about nut Lock never had a issue but I was wondering if using ph tap will do harm

Avoiding nute lock is kinda why I grow in soil. If you're going to use nutes anyway you might as well go hydro is my take...But of course everyone should grow the way they want to.

Soil will buffer that high pH a little, but...pH9 is unusually high for tap water. We have really hard water here, but it's still about ph7, which I thought was "not ideal".

At a minimum you would need to carbon filter that water to try to de-mineralise it I think.