In order to answer this question, I would have to review your lease. Generally, you are obligated to perform the acts that you have agreed to perform, and if you fail to perform such acts, the landlord can sue you for any damages cause by such failure.
You should immediately contact an attorney experienced in landlord and tenant law for more detailed advice based upon the specific facts of your case because this answer is for general educational and guidance purposes only. This answer is based entirely upon the facts that you have provided and could be different if different or additional facts exist.
This answer is for general and educational purposes only and does not establish an attorney-client relationship. An attorney-client relationship will not be established with me unless and until you have executed a written agreement for me to represent you. Nothing you post in this forum is confidential nor is it subject to attorney-client privilege.
As Atty. Miller answered, more details are required. However, if we presume that your lease held you responsible for the lawn, but not to maintain the plumbing, then if you have proof that its failure was not your fault, (ex. failing to winterize?) then after notice to LL, you could have the sprinkler's fixed and deduct the cost from your rent. Then the courts could decide. Your argument is that the LL was to provide the tools to maintain the grass. So, if you let the grass wither, it would be your breach.