Yes the drip system can be left installed for the winter months but you would have to winterize your drip system. We have a “how to” article on how to winterize your irrigation system on our website just follow this link https://www.digcorp.com/winterizing-your-irrigation-system . . If you have any other questions please contact our technical service/ product support line 1-800-344-1172.
No it’s not NSF approved, but it is BPA free. DIG poly tubing is for irrigation purposes only. For drinking water purposes, you should use schedule 40 PVC pipe.
Yes, you can theoretically go to infinity. The limiting factor will be the number of taps off of the line.
You need an adapter
THD has two sizes of drip tubing from DIG, the 0.700 OD and the 0.710 OD. The description for both sizes are very similar with the .710 OD has higher flow capability then the .700 OD. Both sizes can be used with the .700 drip fittings with black inserts and the .710 drip fittings with blue inserts.
This is recommended for drip irrigation. Use of the product is solely at the purchaser's discretion.