Gst registarion on rental+tailoring income

the threshold limit of gst is 20 lakhs for supply of goods or services (includes taxable and exempt) but under a notification the threshold for supply of goods increase to 40lakhs.
in your case total supply is 18.5 lakhs. then no need to take registration.
but if you have taken registration then gst would be applicable only on taxable supplies.

registration on rental income is not required below 20lakhs..gst on tailoring business is chargeable @ 5%..

As per Section 2(6) of the CGST Act 2017, Aggregate Turnover means the aggregate value of all taxable supply (excluding the value of inward supply on which tax is payable by a person on reverse charge basis ), EXEMPT Supply, Export of goods or services or both and Inter State Supply of persons having the same permanent account number to be computed on all India basis but excludes central tax, state tax, Union territory tax, Integrated tax and Cess.

Now if the property is let out for Residential purpose, then the income is Exempt from GST vide Notification No. 12/2017, CT ( RATE ) dated 28.06.2017.

But since Aggregate Turnover also includes Exempt Supply, Rental Income would be taken into consideration while computing your Aggregate Turnover.

Under GST, a person is compulsorily required to take Registration if his Aggregate Turnover exceeds Rs.20 lakhs.

Since your Aggregate Turnover is Rs. 18.5 lakhs ( 3.5 + 15 ), you are not required to take GST Registration.

However you can voluntarily opt for GST Registration as permitted u/s 25(3) of the CGST Act 2017.

Warm Regards.

What Is The Process Of Applying GST For A Firm

 

GST registration not required to above said value...

Now the limit of GST raised to RS 40 lakhs. So there is no need to take GST registration