Hi @albertnein ,
''The impurities in the water causes corrosion and provides circuit paths for the electricity which were not in the laptop's operating design and could damage the components. The corrosion starts immediately and is ongoing until it is completely cleaned away.''
You will have to open the laptop to check the extent of any water damage and corrosion that has occurred
''First ***do not try to charge or to turn on your laptop*** and then ***disconnect the battery as soon as possible*** from the motherboard'' to minimize any further damage.
Here's the [https://download.lenovo.com/consumer/mobiles_pub/thinkbook_13s-14s_iwl_hmm_201905.pdf|hardware maintenance manual] for the laptop.
Go to p.31 to view the procedure to disconnect the battery
Once the laptop is open you will have to clean ''all the affected parts'' using ***Isopropyl Alcohol 99%+*** (available at electronics parts stores) to remove all traces of corrosion and water. If possible do not use "rubbing alcohol" as in some cases this is only 70% IPA or less, can contain additives and is not as effective. If you do have to use it check the label to verify the amount of IPA. The higher the percentage of IPA the better
Here is a link that describes the process. [[Electronics Water Damage|Electronics Water Damage|new_window=true]]
As always with electronics, especially surface mounted pcb be gentle when handling and especially when brushing away the corrosion. You do not want to remove any components from the board. Remove the shields that may be covering some components as the water may have got in under there. The ends of any flex cables and their connectors need to be cleaned as well.
It may well be that the keyboard will have to be replaced as usually when trying to fix keyboards you can create more problems than what you had.
The keyboard is part of the upper case assembly so most probably you will have to get the complete assembly rather than just the keyboard itself. See p.41 of the manual for removal procedure.
Here's the [https://pcsupport.lenovo.com/us/en/products/laptops-and-netbooks/thinkbook-series/thinkbook-14s-iwl/20rm/parts/display/compatible?linkTrack=Caps%3ABody_SearchProduct&searchType=4&keyWordSearch=ThinkBook%2014s-IWL%20Laptops%20-%20Type%2020RM|parts list] for the laptop. Click on ''Select Commodity > C-cover with keyboard (63)'' to find the part number for all the keyboard/uppercase assemblies that are used with the laptop. The keyboards are ''country specific'' as can be seen by the country code at the end of the part name e.g. US (USA), UK (United Kingdom), SW (Switzerland), SP (Spain) etc.
Search online using the appropriate to your model, ''part number only'' to find suppliers that suit you best. Usually the part number can be found somewhere on the underside of the assembly, if you wish to verify that you're ordering the correct one.