Round Rock ADU Builders: ADU Impact Fees & Utility Connection Cost in Texas

Impact Fees and Utility Connection Costs

There is a category of ADU cost that sits outside the construction contract, does not appear in per-square-foot estimates, and arrives as a series of separate invoices. It catches people out regularly, not because the amounts are unreasonable but because nobody put them in the budget.

What These Fees Are

Direct answer: Impact fees are charges levied by a jurisdiction or utility district to fund the infrastructure capacity that new development consumes, typically for water and wastewater. Connection or tap fees cover the physical connection to the system. Meter fees cover the meter itself. Adding a dwelling unit can trigger some or all of these depending on how the unit is served.

They are distinct from the building permit fee, which is usually a much smaller amount and the one people do remember to budget.

Why the Amounts Vary So Much

Fee schedules are set independently by each city and each utility district, and they differ substantially across our service area. A property inside Round Rock city limits, one in Pflugerville, and one served by a municipal utility district in unincorporated county are three different fee structures.

[[VERIFY: verified current impact, connection and meter fee schedules by jurisdiction and utility provider in the service area]]

The variable that matters most is usually whether the ADU is treated as a new service unit requiring its own connection, or as an extension of the existing residential service. That determination is made by the utility, not by you or your builder, and it can change the total considerably.

Separate Meter or Sub-Meter

This decision has both a fee consequence and an operational one.

A separate meter means the ADU has its own account and its own bill. For a rental, this is clean: the tenant pays their own utilities directly and there is no allocation dispute. It typically means paying full connection and impact fees for a new service unit.

Sub-metering from the existing service avoids some of those fees in some jurisdictions, but means the ADU’s usage appears on your bill and must be allocated to the tenant by agreement. It works, but it requires you to read a meter and invoice, and it can create friction.

For family occupancy, sub-metering is usually simpler. For a long-term rental, the cleanliness of separate metering is often worth the higher upfront cost. Which is actually available to you depends on utility policy.

Electrical Service Capacity

A related cost that is not a fee at all: the existing electrical panel may not have capacity for a second dwelling. Older homes in Taylor and the earlier sections of Wells Branch commonly have service sized for the loads of their era.

Where a service upgrade is required, it is work at the primary residence, performed before the ADU can be energized. It is entirely predictable from a panel inspection at the site assessment stage, and entirely disruptive if discovered at final inspection.

What to Ask, and When

Ask your builder directly whether the quote includes permits, impact fees, connection fees, and meter fees, or whether those are owner-paid. Either answer is legitimate. Not knowing which it is is the problem.

Call the utility provider for your parcel and ask what an additional dwelling unit triggers. They answer this routinely.

Have the electrical panel assessed during the site visit rather than later.

Put the total in the budget as its own line. Not folded into a contingency, where it competes with genuine surprises.

None of these fees are unreasonable in themselves. They only cause problems when they arrive unbudgeted at the point where the money has already been committed elsewhere.