Cal. Civ. Code § 3.17

(1) Conditions and Maintenance of a Dwelling Unit. It shall be an unfair or deceptive act or
           practice for an owner to:
              (a) Rent a dwelling unit which, at the inception of the tenancy
                   1. contains a condition which amounts to a violation of law which may endanger or
                   materially impair the health, safety, or well-being of the occupant; or
                   2. is unfit for human habitation;
              (b) Fail, during the terms of the tenancy, after notice is provided in accordance with M.G.L.
              c. 111, § 127L, to
                   1. remedy a violation of law in a dwelling unit which may endanger or materially impair
                   the health, safety, or well-being of the occupant, or
                   2. maintain the dwelling unit in a condition fit for human habitation; provided, however,
                   that said violation of law was not caused by the occupant or others lawfully upon said
                   dwelling unit;
              (c) Fail to disclose to a prospective tenant the existence of any condition amounting to a
              violation of law within the dwelling unit of which the owner had knowledge or upon
              reasonable inspection could have acquired such knowledge at the commencement of the
              tenancy;
              (d) Represent to a prospective tenant that a dwelling unit meets all requirements of law
              when, in fact, it contains violations of law;
              (e) Fail within a reasonable time after receipt of notice from the tenant to make repairs in
              accordance with a pre-existing representation made to the tenant;
              (f) Fail to provide services and/or supplies after the making of any representation or
              agreement, that such services would be provided during the term or any portion of the term
              of the tenancy agreement;
              (g) Fail to reimburse the tenant within a reasonable or agreed time after notice, for the
              reasonable cost of repairs made or paid for, or supplies or services purchased by the tenant
              after any representation, that such reimbursement would be made;
              (h) Fail to reimburse an occupant for reasonable sums expended to correct violations of law
              in a dwelling unit if the owner failed to make such corrections pursuant to the provisions of
              M.G.L. c. 111, § 127L, or after notice prescribed by an applicable law;
              (i) Fail to comply with the State Sanitary Code or any other law applicable to the conditions
              of a dwelling unit within a reasonable time after notice of a violation of such code or law
              from the tenant or agency.

           (2) Notices and Demands. It shall be an unfair or deceptive practice for an owner to:
              (a) Send to a tenant any notice or paper which appears or purports to be an official or judicial
              document but which he knows is not;
              (b) Fail or refuse to accept any notice sent to any address to which rent is customarily sent,
              or given to any person who customarily accepts on behalf of the owner, or sent to the person
              designated in the rental agreement in accordance with 940 CMR 3.17(3)(b)2.

(c) Demand payment for increased real estate taxes during the term of the tenancy unless,
              prior to the inception of the tenancy, a valid agreement is made pursuant to which the tenant
              is obligated to pay such increase.

           (3) Rental Agreements.
              (a) It shall be unfair or deceptive act or practice for an owner to include in any rental
              agreement any term which:
                  1. Violates any law;
                  2. Fails to state clearly and conspicuously in the rental agreement the conditions upon
                  which an automatic increase in rent shall be determined. Provided, however, that nothing
                  contained in 940 CMR 3.17(3)(a)2. shall be deemed to invalidate an otherwise valid tax
                  escalator clause;
                  3. Contains a penalty clause not in conformity with the provisions of M.G.L. c. 186, §
                  15B;
                  4. Contains a tax escalator clause not in conformity with the provisions of M.G.L. c.
                  186, § 15C;
              (b) It shall be an unfair or deceptive practice for an owner to enter into a written rental
              agreement which fails to state fully and conspicuously, in simple and readily understandable
              language:
                  1. The names, addresses, and telephone numbers of the owner, and any other person
                  who is responsible for the care, maintenance and repair of the property;
                  2. The name, address, and telephone number of the person authorized to receive notices
                  of violations of law and to accept service of process on behalf of the owner;
                  3. The amount of the security deposit, if any; and that the owner must hold the security
                  deposit in a separate, interest-bearing account and give to the tenant a receipt and notice
                  of the bank and account number; that the owner must pay interest, at the end of each year
                  of the tenancy, if the security deposit is held for one year or longer from the
                  commencement of the tenancy; that the owner must submit to the tenant a separate
                  written statement of the present condition of the premises, as required by law, and that,
                  if the tenant disagrees with the owner's statement of condition, he/she must attach a
                  separate list of any damage existing in the premises and return the statement to the
                  owner; that the owner must, within thirty days after the end of the tenancy, return to the
                  tenant the security deposit, with interest, less lawful deductions as provided in M.G.L.
                  c. 186, § 15B; that if the owner deducts for damage to the premises, the owner shall
                  provide to the tenant, an itemized list of such damage, and written evidence indicating
                  the actual or estimated cost of repairs necessary to correct such damage; that no amount
                  shall be deducted from the security deposit for any damage which was listed in the
                  separate written statement of present condition or any damage listed in any separate list
                  submitted by the tenant and signed by the owner or his agent; that, if the owner transfers
                  the tenant's dwelling unit, the owner shall transfer the security deposit, with any accrued
                  interest, to the owner's successor in interest for the benefit of the tenant.
              (c) It shall be unfair and deceptive practice for an owner to fail to give the tenant an
              executed copy of any written rental agreement within 30 days of obtaining the signature of
              the tenant thereon.

           (4) Security Deposits and Rent in Advance. It shall be an unfair or deceptive practice for an
           owner to:
              (a) require a tenant or prospective tenant, at or prior to the commencement of any tenancy,
              to pay any amount in excess of the following:
                  1. rent for the first full month of occupancy; and
                  2. rent for the last full month of occupancy calculated at the same rate as the first month;
                  and
                  3. a security deposit equal to the first month's rent; and,
                  4. the purchase and installation cost for a key and lock.
                  or, at any time subsequent to the commencement of a tenancy, demand rent in advance
                  in excess of the current month's rent or a security deposit in excess of the amount allowed
                  by 940 CMR 3.17(4)(a)3.

(b) fail to give to the tenant a written receipt indicating the amount of rent in advance for
              the last month of occupancy, and a written receipt indicating the amount of the security
              deposit, if any, paid by the tenant, in accordance with M.G.L. c. 186, § 15B;
              (c) fail to pay interest at the end of each year of the tenancy, on any security deposit held
              for a period of one year or longer from the commencement of the term of the tenancy, as
              required by M.G.L. c. 186, § 15B;
              (d) fail to hold a security deposit in a separate interest-bearing account or provide notice to
              the tenant of the bank and account number, in accordance with M.G.L. c. 186, § 15B;
              (e) fail to submit to the tenant upon receiving a security deposit or within ten days after
              commencement of the tenancy, whichever is later, a separate written statement of the present
              condition of the premises in accordance with M.G.L. c. 186, § 15B;
              (f) fail to furnish to the tenant, within 30 days after the termination of occupancy under a
              tenancy-at-will or the end of the tenancy as specified in a valid written rental agreement, an
              itemized list of damage, if any, and written evidence indicating the actual or estimated cost
              of repairs necessary to correct such damage, in accordance with M.G.L. c. 186, § 15B;
              (g) fail to return to the tenant the security deposit or balance thereof to which the tenant is
              entitled after deducting any sums in accordance with M.G.L. c. 186, § 15B, together with
              interest, within thirty days after termination of occupancy under a tenancy-at-will agreement
              or the end of the tenancy as specified in a valid written rental agreement;
              (h) deduct from a security deposit for any damage which was listed in the separate written
              statement of present condition given to the tenant prior to execution of the rental agreement
              or creation of the tenancy, or any damages listed in any separate list submitted by the tenant
              and signed by the owner or his agent;
              (i) fail, upon transfer of his interest in a dwelling unit for which a security deposit is held,
              to transfer such security deposit together with any accrued interest for the benefit of the
              tenant to his successor in interest, in accordance with M.G.L. c. 186, § 15B;
              (j) fail, upon transfer to him of a dwelling unit for which a security deposit is held, to
              assume liability for the retention and return of such security deposit, regardless of whether
              the security deposit was, in fact, transferred to him by the transferor of the dwelling unit, in
              accordance with M.G.L. c. 186, § 15B; provided, that 940 CMR 3.17(4)(j) shall not apply
              to a city or town which acquires property pursuant to M.G.L. c. 60 or to a foreclosing
              mortgagee or a mortgagee in possession which is a financial institution chartered by the
              Commonwealth or the United States, or;
              (k) otherwise fail to comply with the provisions of M.G.L. c. 186, § 15B.
                  940 CMR 3.00 shall not be deemed to limit any rights or remedies of any tenant or other
              person under M.G.L. c. 186, §§ 15B(6) or (7).

           (5) Evictions and Termination of Tenancy. It shall be an unfair and deceptive practice for an
           owner to:
              (a) Deprive a tenant of access to or full use of the dwelling unit or otherwise exclude him
              without first obtaining a valid writ of execution for possession of the premises as set forth
              in M.G.L. c. 239 or such other proceedings authorized by law;
              (b) Commence summary process for possession of a dwelling unit before the time period
              designated in the notice to quit under M.G.L. c. 186, §§ 11 and 12, has expired; provided,
              however, nothing in 940 CMR 3.17 shall effect the rights and remedies contained in M.G.L.
              c. 239 § 1A.

           (6) Miscellaneous. It shall be an unfair and deceptive practice for an owner to:
              (a) Impose any interest or penalty for late payment or rent unless such payment is 30 days
              overdue;
              (b) Retaliate or threaten to retaliate in any manner against a tenant for exercising or
              attempting to exercise any legal rights as set forth in M.G.L. c. 186, § 18;
              (c) Retain as damages for a tenant's breach of lease, of the failure of a prospective tenant
              to enter into a written rental agreement after signing a rental application, any amount which
              exceeds the damages to which he is entitled under the law, or an amount which the parties
              have otherwise agreed as to the amount of the damages;

(d) Require payment for rent for periods during which the tenant was not obligated to
              occupy and did not in fact occupy the dwelling unit unless otherwise agreed to in writing by
              the parties;
              (e) Enter a dwelling unit other than (i) to inspect the premises, or (ii) to make repairs
              thereto, or (iii) to show the same to a prospective tenant, purchaser, mortgagee or its agents,
              or (iv) pursuant to a court order, or (v) if the premises appear to have been abandoned by the
              tenant, or (vi) to inspect, during the last 30 days of the tenancy or after either party has given
              notice to the other of intention to terminate the tenancy, for the purpose of determining the
              amount of damage, if any, to the premises which would be cause of reduction from any
              security deposit held by the owner.
              (f) To violate willfully any provisions of M.G.L. c. 186, § 14.
              (g) It shall be an unfair practice for any owner who is obligated by law or by the express or
              implied terms of any tenancy agreement to provide gas or electric service to an occupant:
                  1. To fail to provide such service; or
                  2. To expose such occupant to the risk of loss of such service by failing to pay gas or
                  electric bills when they become due or by committing larceny or unauthorized use of
                  such gas or electricity. For the purpose of this regulation a bill shall be deemed "due"
                  only after the owner has had an opportunity to contest it at a Department of Public
                  Utilities hearing or any appeal from such hearing during which termination of service has
                  been stayed.