Decibels may lead to confusion as there are dozens of them! Why? It's a logarithmic ratio, a division with different denominators so you could count as many types of decibels as possible numbers to establish the reference.
A usual one is dBu, where the reference denominator is 0.7746 volts and the numerator is root mean square voltage. If you have 1 volt of RMS voltage, the calculation is:
20 * log10 ( 1 / 0.7746) = ~2.2185 dBu
The dB must be logarithmic as the ear system processes audio logarithmically!
Here are some common, rough values in dBA, the A-weighted decibels... This means how the human ear system perceives sound and it's corrected due to the lesser definition in low frequencies:
20 dB(A) Quiet room
60 dB(A) Normal conversation (without dishes flying)
90 dB(A) Electric hand tool, noisy
[ Protection very recommended ]
110 dB(A) Live concert
120 dB(A) Pain threshold
140 dB(A) Jet turbine, near
At residential areas, perhaps 65 - 60 dB are widely allowed, sometimes a bit more.