Property Owner Contention of Violation Letter

Our small (11 Units) HOA has gone by the board over the years without much proactive effort by previous BOD members.
In an effort to correct this and to bring the community up to the standards set by the CC&R's, the present board has pursued a more hands-on and proactive stance. Goals have been agreed upon, tasks assigned and completed. A review of our governing documents has been completed and review of our financials was also accomplished.
To get to the point, one of the tasks laid out was to also issue "Letters of Violation" for those property owners who were not conforming to our CC&R's requirements.
One of the property owners whom received a letter is contesting this action. The issue is that he has let his lawn die.
Originally,when he began contesting the issue, he stated that one of the sprinkler heads on his systems water loop was broken and spewing water. This was corrected within 72 hours. Now, he is stating that he will not further pursue correcting his landscape violation because the same sprinkler head waters three shrubs in a "common area".
This condition has existed since 1993, when the development was completed. He purchased the property 10 years later.
He also expects the HOA to reimburse him for the cost of the water expended on those three shrubs, over his tenure as property owner.
Questions:
(a). Is the HOA obligated to correct the issue regarding the property owners argument with the configuration of his sprinkler system?
(b). Is the HOA obligated to reimburse him for the expense of water used in the irrigation of the three "common area" shrubs over the course of his tenure as property owner?

Any feedback would be greatly appreciated.

Thanks for the input, Melissa!
Each property owner has a separate irrigation system, aside from the accepted "common areas", which are watered, metered and paid by the HOA. The property owner in question has the ability to elect not to water the shrubbery in question by not engaging that part of his irrigation system which waters that shrubbery.

Melissa,

I see that in your original response you had asked about the sprinkler systems.
These were installed by the developer in the the original construction of the complex. Each property has a meter and the larger common area has a separate meter, which the HOA is billed from.
Yes, we have a fining schedule in place. One benefit to our efforts was that about two months ago, there was an HOA training symposium that two of our board members were able to attend (I was out of town).
The training symposium mostly dealt with the impact of the Davis/Sterling Act and how that affected CA HOA's.
Taking from that meeting, we were able to review our documents and identify what needed to be changed or corrected and one of those efforts was to put a fining schedule in place that was more definitive than what had previously existed.