- Monthly utility cost for a 600 sqft LA ADU (1 to 2 occupants, 2026): $150 to $300 combined — electricity $90 to $160, water and sewer $40 to $70, trash $30 to $50.
- Separate LADWP meter: $2,000 to $5,000 upfront connection fee. Tenant gets their own bill. Highest upfront cost, lowest long-term landlord risk.
- Sub-meter: lower install cost (often $500 to $1,500), but the homeowner remains legally responsible to LADWP for the full bill. You bill the tenant back.
- The capacity surprise: about half of LA homes built before 1970 carry a 100-amp main panel that cannot safely add a full ADU load. Upgrade to 200 amps runs $2,500 to $4,500 and is a permitting requirement, not optional.
- Title 24 solar mandate applies to most new detached ADUs and can drop the electricity component below $50/month in shoulder seasons. Sometimes the right answer is not to build — and we say that clearly, before any money moves.
Monthly Utility Cost Breakdown
Numbers below assume one or two occupants, LADWP tiered residential rates, and a unit built to current Title 24 standards. Larger units (700 to 1,200 sqft), heavier occupancy, or pre-2020 builds with weak insulation will run higher.
Electricity — $90 to $160/month
LADWP uses a tiered residential rate structure. The more electricity a household uses in a billing period, the higher the rate per kWh on the upper tiers. An ADU adds a second household to the lot. If the unit is on the main house’s meter, that combined usage often pushes the property into Tier 2 or Tier 3 territory for every kWh consumed, including the kWh the main house was already using.
Drivers that push electricity to the upper end of the range:
- Heat-pump vs. resistance HVAC. A ductless mini-split heat pump uses roughly one third the electricity of resistive heating for the same indoor temperature. The delta is $30 to $60/month in winter.
- Electric water heating. All-electric ADUs (increasingly required under local reach codes) shift hot water onto the electric bill. Heat-pump water heaters cut that load by about 60% vs. standard electric resistance.
- EV charging. A Level 2 charger shared with the ADU can add 200 to 400 kWh/month, which is meaningful at tiered rates.
Water and sewer — $40 to $70/month
LADWP bills water; the city’s sewer service charge is bundled on the same statement. For a low-occupancy ADU with current low-flow fixtures, water typically runs $25 to $45/month. The sewer service charge runs an additional $15 to $25/month. Heavy laundry use, irrigation tied to the ADU, or a tub-soaking habit will push the combined bill above this range.
Trash, recycling, and green waste — $30 to $50/month
LASAN handles solid resources collection. For most ADU configurations, the unit is added to the existing property’s container service and the homeowner pays a single combined bill. Separate ADU service is available in some configurations but is rarely cost-effective.
Meter Configuration
The single decision that affects long-term landlord exposure on a rental ADU is which meter configuration was specified at permit. Once construction is done, retrofitting from shared to separate runs roughly 2 to 3 times the cost of doing it during the original build.
Separate LADWP Meter (Dedicated Service)
Sub-Meter (Homeowner Remains Account Holder)
All-Inclusive Utilities (Rolled Into Rent)
For a long-term rental ADU sized 600 sqft or larger, the separate LADWP meter path is the right default, even at the higher upfront cost.
The Capacity Upgrades Nobody Mentions Until Permit Review
These are not utility costs in the monthly sense. They are one-time construction costs that show up between Feasibility and Permit, and they catch homeowners off guard because the original contractor bid rarely includes them.
Main electrical panel upgrade
The trigger: about half of LA homes built before 1970 carry 100-amp main service. Adding a 600 sqft ADU with electric heating, electric cooking, and electric water heating typically pushes the load calculation above what 100 amps can safely carry. LADBS will require a 200-amp upgrade before signing off on the electrical permit. The upgrade includes new service entrance conductors, a new main panel, and an LADWP service-drop coordination visit.
Sewer lateral upgrade
The trigger: in older LA neighborhoods (Highland Park, Mar Vista, parts of the Eastside), original clay sewer laterals are often at capacity for a single household. Adding an ADU triggers a city requirement to upgrade the lateral. This is one of the three most common reasons a paid Feasibility & Risk Assessment returns “do not build on this lot as scoped.”
Trenching for distant ADUs
If the ADU footprint is more than ~40 feet from the existing main lines, the cost of running new water, sewer, and electrical trenches scales linearly. A backyard ADU placed 100 feet from the main house adds roughly $5,000 to $10,000 in trenching that the architectural plans often don’t surface until structural review.
Sewer Capacity Charge (large units only)
Adding three or more bathrooms across a property (main house plus ADU combined) can trigger an LA Department of Public Works Sewer Capacity Charge above the standard connection fee. For a 1-bathroom ADU on a 2-bathroom main house, this rarely triggers.
Title 24 Solar and All-Electric Rules
California’s Title 24 energy code requires photovoltaic systems on most new detached residential construction. For an ADU, this often translates to a 2 to 3 kW rooftop solar array sized to the unit’s expected annual electrical load.
In practice, the solar mandate does three things to the monthly utility bill:
- 1 Cuts the electricity component to the LADWP service minimum (around $20/month) in spring and early summer when production is high and demand is moderate.
- 2 Smooths winter bills, when production is lower but the unit is still net-positive on most days.
- 3 Reduces but does not eliminate exposure to LADWP’s tiered rate structure when the main house plus ADU runs heavy load on a non-net-metered configuration.
Some LA County jurisdictions and reach-code cities have moved to all-electric requirements for new ADUs, which removes the natural gas line cost ($1,500 to $4,000 one-time) and the monthly gas service charge but increases the electrical load that solar offsets.
ADU Utility Costs, LA, 2026
Standard 600 sqft LA ADU monthly utility load: $150 to $300 combined — $90 to $160 electric via LADWP, $40 to $70 water and sewer via LADWP, $30 to $50 solid resources via LASAN.
Separate LADWP meter set: $2,000 to $5,000 in 2026 fees, before panel and subpanel work. Total separate-service install: $4,500 to $9,500.
Main panel upgrade (100A to 200A) triggers in roughly half of pre-1970 LA homes adding a full-load ADU. Cost: $2,500 to $4,500 per LADBS requirements.
California Title 24 solar mandate applies to most new detached ADUs per the California Energy Commission, reducing the electricity component in shoulder seasons.
State law waivers (AB 68, SB 13): for ADUs under 750 sqft, sewer connection fees and most impact fees are waived under California state law. Confirmed in Gov Code §65852.2.