IPTables - Allow only traffic from specific ranges

I am trying to block all traffic to a webserver except from some defined subnets. I've checked numerous posts and believed I had iptables set correctly but for some reason the site is still accessible outside the subnets i've defined in the ruleset. Is anyone able to shed some light on what I may have done wrong? I've established that removing rule 3 stops the site from being reachable at all. The site itself sits in 10.10.0.0/16.

Chain INPUT (policy DROP 0 packets, 0 bytes)
num   pkts bytes target     prot opt in     out     source               destination         
1        0     0 ACCEPT     all  --  any    any     10.10.0.0/16         anywhere            
2        0     0 ACCEPT     all  --  any    any     172.30.0.0/16        anywhere            
3        0     0 ACCEPT     all  --  lo     any     anywhere             anywhere            

Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
num   pkts bytes target     prot opt in     out     source               destination         

Chain OUTPUT (policy ACCEPT 0 packets, 0 bytes)
num   pkts bytes target     prot opt in     out     source               destination         
1        0     0 ACCEPT     all  --  any    lo      anywhere             anywhere

The goal will be to add various whitelisted public IPs and lockdown the site so that it is only accessible to some. Rules were added as follows:

iptables -I INPUT -i lo -j ACCEPT
iptables -I OUTPUT -o lo -j ACCEPT
iptables -I INPUT -s 10.10.0.0/16 -j ACCEPT
iptables -I INPUT -s 172.30.0.0/16 -j ACCEPT
iptables -P INPUT DROP