Rain Gardens & Cisterns for Hill Country Lots in 78260

Big summer downpours one week and dry spells the next can be hard on a Timberwood Park yard. On shallow, rocky soils and sloped driveways, runoff moves fast and can take your mulch with it. If you want to slow the water, protect your landscape, and make the most of every inch of rain, a rain garden and a cistern can work together. This guide walks you through local rules, smart sizing, plant choices, costs, and rebates for 78260. Let’s dive in.

Why these systems fit Timberwood Park

Timberwood Park sits on the edge of the Hill Country, where soils are thin and limestone is close to the surface. That means infiltration can be spotty and erosion can happen fast. A rain garden temporarily holds and filters roof and driveway runoff, then drains within a day or two. A cistern stores roof water for later use in your landscape. Used together, you capture water for plants and route overflow to a stable, planted area that reduces erosion. Texas A&M’s rain garden guidance explains how a well‑built garden drains quickly and benefits pollinators, too (TAMU rain garden guide).

Start with a quick site check

Confirm POA and utility basics

Before you dig, review Timberwood Park POA expectations for visible landscaping and structures. The neighborhood site is a good starting point for contacts and approvals (Timberwood Park POA). Also confirm your water provider since rebate options vary. Many homes are served by SAWS, though some are not (SAWS service areas).

Check Edwards Aquifer rules

Parts of northern Bexar County sit over the Edwards Aquifer’s regulated zones. If your lot is in a recharge or contributing zone, certain earthwork and storage installations may need preapproval. Use the Edwards Aquifer Authority map to see what applies to your address (EAA regulatory maps). For permit details, see the TCEQ Edwards Aquifer Protection Program (TCEQ EAPP).

Map setbacks and test infiltration

Locate your septic components and any wells, and call 811 to mark utilities before digging. Keep rain gardens at least 10 feet from foundations and away from septic drainfields. Then do a simple infiltration test to confirm your soil will drain within 24 to 48 hours. If you encounter very shallow rock, plan for imported media or a raised bioretention bed per extension guidance (TAMU rain garden guide).

Rain garden basics for Hill Country lots

Siting that protects your home

• Place the garden where water already flows, on a low‑slope area if possible.
• Keep at least 10 feet from the house. Avoid utility easements, septic fields, and large tree root zones.
• On steeper sites, add small terraces, a dry creek, or a stone edge to slow and spread water. EPA guidance highlights erosion control and stable overflow routes (EPA rain garden design concepts).

Sizing the bowl

A quick rule of thumb is to size the garden to about 10 to 25 percent of the roof or driveway area draining to it, depending on how fast your soil drains. Many homeowners target capturing about a 1 to 1.5 inch storm from the contributing roof area. Example: a 1,500 square foot roof can produce roughly 700 to 900 gallons in a small storm. A 100 square foot garden with 6 to 12 inches of effective storage can hold a useful share of that event (TAMU rain garden guide).

Soil and construction on rock

Shallow, calcareous soils are common in Timberwood Park. If your infiltration test is slow or you hit rock, import an engineered rain garden mix and consider a shallow, raised bed with a stone border. Use a level bottom, a stable inlet, and a defined overflow that leads to a mulched swale or dry creek lined with rock to prevent erosion (EPA rain garden design concepts).

Plants that handle wet to dry

Choose Texas natives that can take brief saturation then long dry periods. Group by zone:

• Center wet zone: rushes and sedges
• Middle zone: salvias, coneflower, mistflower
• Outer dry edge: little bluestem, muhly, Texas sage

Regional plant lists and examples are available through local Master Gardener and native plant resources (Hill Country plant list).

Maintenance that pays off

Rain gardens are low tech but need checks. After big storms, inspect the inlet and outlet, rake out sediment, and top off mulch. In year one, expect some weeding and plant replacement. A well‑mulched garden drains faster and establishes quicker (TAMU rain garden guide).

Cisterns that work with your slope

Sizing in minutes

Use this simple formula: roof area in square feet × rainfall in inches × 0.623 equals gallons captured per storm. For example, a 1,500 square foot roof with a 1.25 inch rain can yield about 935 gallons. Choose a tank size that fits your space and typical storm patterns, then route overflow to your rain garden (SAWS rainwater harvesting).

Materials and budget

Above‑ground polyethylene tanks are common and cost effective. Fiberglass, steel, and concrete options offer more durability or a specific look. Small above‑ground systems can be under a thousand dollars. One to three thousand gallon systems often run in the low thousands, while large buried systems can reach the tens of thousands. Get site‑specific quotes that include pads, plumbing, and pumps.

Overflow and erosion control

Every cistern needs a safe overflow plan. Direct the outlet into a stable swale, a rock‑lined dry creek, or your rain garden. On slopes, step the flow with check stones or terraces so you do not concentrate water downslope. Local examples promote pairing tanks with rain gardens for cleaner overflow and added infiltration (GardenStyle SA overview).

Rebates, permits, and local rules

• SAWS offers residential rainwater harvesting rebates for customers who install at least 500 gallons of storage. Education steps, registration, and inspections may apply. Check current caps and requirements before you buy a tank (SAWS rainwater harvesting).
• If your lot is in an Edwards Aquifer regulated zone, certain earthwork or storage installations may need a review. Start with the EAA map, then confirm steps with TCEQ’s program pages (EAA regulatory maps, TCEQ EAPP).
• Buried tanks, plumbing tie‑ins, or major grading can trigger permits or POA approvals. Use the POA site for contacts and processes (Timberwood Park POA).

Simple plan for your Timberwood Park property

1. Watch a rain event and sketch where water flows. Note slopes, low spots, and safe overflows.
2. Contact the POA for any approval steps on visible structures and landscaping (Timberwood Park POA).
3. Check your address on the Edwards Aquifer Authority map. If regulated, review TCEQ steps before earthwork (EAA regulatory maps, TCEQ EAPP).
4. Confirm your water provider and the SAWS rebate process if you qualify (SAWS rainwater harvesting).
5. Do a soil infiltration test, then size a rain garden and choose native plants suited to wet and dry zones (TAMU rain garden guide, Hill Country plant list).
6. If you add a cistern, size it with the rainfall formula and route overflow into your rain garden for extra treatment and erosion control (GardenStyle SA overview).

Typical costs at a glance

• Rain gardens: DIY projects can be modest. Professional builds range roughly 3 to 20 dollars per square foot, with terracing and rockwork toward the high end. Many municipal programs budget 20 to 40 dollars per square foot for incentives (Rain garden cost context).
• Cisterns: Small above‑ground tanks can be under a thousand dollars. Basic 1,000 to 3,000 gallon systems often cost in the low thousands, while large buried systems can reach 10,000 to 20,000 dollars or more depending on excavation and pumps.

Ready to make your Timberwood Park lot work with the weather, not against it? If you are planning improvements before a sale or want to boost long‑term curb appeal and comfort, connect with Kristi Waite for neighborhood‑smart advice on what resonates with buyers in 78260.

FAQs

What is a rain garden and how fast should it drain?

• A rain garden is a shallow, planted basin that holds and filters runoff, then drains within about 24 to 48 hours when designed correctly (TAMU rain garden guide).

How do I know if Edwards Aquifer rules affect my lot in 78260?

• Enter your address in the Edwards Aquifer Authority map to see if you are in a regulated zone, then follow TCEQ steps if permits apply (EAA regulatory maps, TCEQ EAPP).

How big should my cistern be for a Timberwood Park home?

• Multiply roof area by inches of rain and by 0.623 to estimate gallons per storm, then choose a size that matches your landscape use and space (SAWS rainwater harvesting).

What plants work in a Hill Country rain garden?

• Use native species by moisture zone: wet‑tolerant sedges in the center, perennials like salvia in the middle, and drought‑tough grasses and shrubs on the outer edge (Hill Country plant list).

Are there rebates for Timberwood Park homeowners?

• If you are a SAWS customer, you may qualify for rainwater harvesting rebates and related education programs; confirm eligibility and steps on the SAWS site (SAWS rainwater harvesting).